Unlike fellow Red Sox top prospect Triston Casas, Bobby Dalbec may be close to his Major League debut. In 2019, Dalbec did plenty of damage at Double-A Portland in the Atlantic League. His first 30 game stint  was encouraging, hitting 7 home runs without embarrassing himself. Dalbec will be 25 in June 2020, so very soon the Red Sox will want to see what they really have in their top prospect. Like Casas, Dalbec has immense raw power, rated a 70 on the 20-80 scouting scale. Also Like Casas, Dalbec has a below average hit tool, meaning he doesn't really hit for average. Unlike Casas, he may never develop into more than a .250 hitter at the MLB level. 

However, Dalbec has other things going for him. Dalbec has much more advanced plate discipline and tons of walks at Double-A. He has also been trimming his strikeout rate Which is another good sign. The only troubling thing so far is he walked very little on his promotion to Triple-A Pawtucket. That can partially be explained away by Dalbec potentially trying to prove himself at the minors most advanced level. He did show the power and didn't strike out more than he did at Portland.

The other plus with Dalbec perhaps is what will make him a much better real life player than may be ever reflected in his card prices. Casas may be a passable third baseman with his above average arm, but his future is likely as a slightly better than average first baseman on defense. On the other hand, Dalbec projects to be a better than average fielder with an excellent arm at the hot corner. Because he is likely much more versatile on defense, the Red Sox may be happy to just have him for his fielding ability and take any power he offers as a binus.

Obviously, Dalbec looks to be a nice useful player. But being on the doorstep of the major leagues with really only raw power, walk, and nice fielding skills to his credit, is there much potential for the hobby to embrace him?

Bobby Dalbec's key rookie card is 2016 Bowman Chrome Draft. While his auto is popular, it still sells for less than that of Single-A slugger Triston Casas. Is Dalbec undervalued, especially being so close to the majors? Or are hobby prospectors more intrigued by Casas' ceiling? Both have plenty of prospect hype, but Dalbec can likely help very soon at the MLB level. Considering you can find his base Chrome - and even the refractor - very recently in the dollar bin, he could be a nice player to hoard and flip very soon if that's what you'd like to do.

The big question is Dalbec ready for regular MLB duty. Many prospect evaluators Believe he has more room to grow. His Autos aren't super cheap, and there still is some prospect hype baked into thatorice. A lot has to do with how the Red Sox front office handles him. The red sox may not be the team he starts for in the near future, as the Red Sox may need to evaluate whether Dalbec is better off as a trade chip as they try to creatively rework their roster.

Of course, staying with the Red Sox may be good for his future, but if he can  become a starter somewhere else and succeed, that’s even better for both Dalbec and his rookie cards. In any case, Dalbec seems to be very close to Major League action. Whether he becomes a backup corner infielder, a second-division starter (that is, for a below-average team), or an all-star is all up to how he fares once thrown into the MLB fire. His base Chrome would be my choice, although his auto is still cheap enough that if you believe he can carry his power, arm, and glove to a starting job somewhere, it’s worth a look.

by     Phoenix Desertsong, Big Huge Red Sox Crazy Fan

Triston Casas is the type of baseball prospect that hobby prospectors salivate over. Many scouts believe that the Red Sox top prospect could develop into a middle of the batting order hitter. His Raw Power scouting grade from FanGraphs is a 70 with 80 potential - 80 being the top grade. His current in-game power grade is a 35 with a 65 potential. 

As for results, his 137 wRC+ mostly at A-ball is fine, and just turning 20 and graduated to High-A ball, he still projects as at least an average Major League player. The big question with him is if his hit tool - ability to hit for average - will rise from the current 25 to the potential 50. The good news is he doesn’t strike-out a ton for a young power hitter and he does take some walks, so his profile is actually pretty good.

His key rookie card is the 2018 Bowman Chrome Draft Auto. The last raw one that sold on eBay was mid October 2019 for $49.99 plus $3.50 shipping. We’ll call it a $50 to $55 card. The cheapest you’ll find on eBay the night of this writing is $60.

There are a couple of other Bowman Chrome Draft autos of Casas that are selling, however, that include the Class of 2018 auto (the refractor numbered to 250) and the Draft Night auto (refractors numbered to 99 and gold refractors numbered to 50). These are attractive targets because there are simply so few of them. The class of 2018 refractor auto you can find for about $40 plus shipping. The draft night auto you’ll be lucky to find for $85 - that comp is already graded PSA 10.

As a collector, I actually favor the serial numbered autos, but my opinion is that the refractors of the 2018 Bowman Chrome Draft auto are the best investment for ROI. That’s because it’s his official 1st Bowman card and the card with the biggest market. That being said, having already graded copies of extremely limited edition cards is a nice “go for broke” strategy. If you want to play it safe, there’s the non-auto 2018 Bowman Chrome Draft which you can find in high grade for $15-20. 

Personally, I’d play it safe with Casas for the time being. Yes, he is the #1 Red Sox prospect, but he just hit .254 at A-ball. Yes, his batting eye is decent and he made noise when he did make contact. I need to see more progress before I would invest in his future, outside of maybe some raw Chrome 1st Bowman cards or colored parallels of his base Bowman Draft card.

All of these points about buying and selling sports cards are just my own informed opinions. They should NOT be taken as professional investment advice. Always do your own research, as the card market can shift drastically without much notice. Remember, this is a hobby, so you must be prepared to be stuck holding any cards you collect.

Transparency notice: As of this writing, I currently own no Triston Casas cards, but may purchase some Chrome base cards or colored parallels purely for Personal Collection purposes.

by   Phoenix Desertsong, Pedro Martinez Fans for Life

While not one of Pedro Martinez’s premier rookie cards, the 1992 Donruss card from their “The Rookies” subset has a few things going for it. First off, this card does feature Pedro in a major league uniform, in Dodger Blue wearing his familiar number #45. Secondly, unlike previous editions of “The Rookies,” Donruss actually released this set in packs rather than in a boxed set. Why is that good? It means that gem mint copies of this card are much harder to find than you’d expect.

There are 2075 graded examples of the 1992 Donruss Rookies Pedro Martinez card, yet only  275 of those have graded out as a PSA 10 Gem Mint. There are 1295 PSA 9 examples, which is why that’s what you’ll much more commonly find for sale.

As a serious Pedro Martinez collector, you’ll most likely want the PSA 10. In late 2019, you can find PSA 9 copies for about $15-20, but the PSA 10 copies tend to be $30 or more. You’ll find a similar case for Pedro’s former teammate, Manny Ramirez, who actually has a whopping 2500 graded examples of his card in the set, yet only 270 graded PSA 10. That card, interestingly has similar price points. So, it’s pretty cool to have these two in the same set.

(It’s worth noting that Tim Wakefield also has a rookie card in the set, as well as all-star second baseman Jeff Kent. Of course, Wakefield doesn’t have many graded examples, although neither does Kent, interestingly enough.)

Of course, this card also depicts Pedro on the mound. Many of his early cards do not. I’ve also always preferred rookie cards with players in Major League uniforms, which is something I know many collectors prefer. All in all, this is a pretty nice and affordable Pedro Martinez rookie card that still holds some value from the Junk Wax era when graded PSA 9 or better.

by  Phoenix Desertsong, Baseball Stat Fanatic

Previously, we looked at Justin Smoak and his unlucky run with batted balls in 2019. As it turns out, there was someone else just as unlucky as Smoak with a similar profile. That guy is C.J. Cron, previously of the Minnesota Twins. A first base/DH type like Smoak, Cron has a couple things in his favor that make him a bit more exciting as a speculative sports card or fantasy baseball investment.

When this piece was first written, Cron was still officially a member of the Minnesota Twins. But since then, he was non-tendered and banished along with Smoak to free agency. These are the same 2019 Twins that broke the regular season home run record after all. Cron was part of that, belting 25 taters of his own. But,  despite better surface numbers than his StatCast expected wOBA buddy Smoak, he finished with almost identical actual and expected wOBA marks.

The major difference with Cron is his not so elite walk rate. A lot of Smoak's value comes from his elite plate discipline. Cron's is more obvious. Coming off a super good year with the Rays, he was non-tendered by the cost conscious Tampa Bay team and picked up by the shrewd Twins. The move actually paid off for Minnesota, at least from a StatCast perspective. (The Rays replaced Cron with Avisail Garcia, which worked out fine.)

Cron had a career high in average batted ball exit velocity (91 mph) and barrel percentage (15 percent). These marks contributed to an expected .273 batting average and .530 slugging percentage. Even with his average 5.8 percent walk rate, he was a pretty nice hitter with an expected .366 wOBA.

Unfortunately, Cron's actual results fell short of those marks. He had a .253 batting average and a .469 slugging percentage in "real life." Those numbers fall in line with his career averages, which may lead casual observers to say, hey he is what he is. But, we are not casual. It seems that Cron did actually grow as a hitter with Tampa. He actually improved in 2019. It just didn't show on the back of his baseball card.

Going into just his age 30 season, Cron could have yet another career year like he did in 2018. The rolling expected wOBA chart shows he really only had one bad month (July) and a couple of bad stretches in September. In 2018, he had one truly awful stretch in late June through mid July. Seeing the consistency of expected numbers above league average is a good sign going forward.

Like with Smoak, C.J. Cron rookie cards are not popular. However, his 2011 Bowman Chrome Auto has sold a fair amount of times on eBay. The prices are quite varied. But, the most notable sale was a Gold Refractor numbered to a mere 50 copies graded 9.5 Gem Mint and a 10 auto sold for roughly $45 shipped. Raw copies of the base Chrome Auto have sold for anywhere between $6 and $12 shipped.

Of course, it seems the best investment is the BGS 9.5 autos, especially the refractors, which are limited to 500 copies. Note that a graded non-refractor brought only $11.50 in July. But, another copy of that card brought $21 in early August. A refractor, though, brought $23 in late August. Clearly the refractor is a better value.

Now with the Detroit Tigers, C.J. Cron can be expected to share the first base/designated hitter duties with Miguel Cabrera. What prices can we expect for Cron graded rookie refractor autos if he breaks out? It wouldn't be a surprise if his refractors get to be around $35 if he gets hot. The only issue is that the Tigers are headed to nowhere.

However, it's entirely possible that Cron becomes a Trading Deadline trade chip. If Cron performs well, he could end up being dealt to a playoff contender. If Cron is traded, gets hot on a team that makes the playoffs, and becomes a major factor in a playoff run, his cards could get hot. Then, $50 for one of his Bowman Chrome rookie refractor autos isn't out of the question. If you can get a steal on a refractor graded BGS 9.5 with 10 auto, it may be worth a shot. Just mind the hot streaks and you may have a nice flip.

Now, he just has to live up to those expected batted ball numbers, and find a playoff team...

by  Phoenix Desertsong, Baseball Stat Freak

Justin Smoak was one of the unluckiest hitters in baseball in 2019. According to StatCast, he was the 9th unluckiest hitter in terms of xwOBA minus actual wOBA. That 9th place is misleading as a  bunch of the guys ahead of him are backup catchers or utility type players. There are only a couple of guys we'd even care about as far as fantasy or rookie cards are concerned. Those two are Marcell Ozuna and Kendrys Morales.

As for Smoak, his quality of contact suggests his .208 batting average and .406 slugging percentage are much too low. StatCast expected a .245 batting average, which is also his career average. For slugging, StatCast expected a .476 mark, also not far off of his career average.  With his career high 15.8 percent walk rate in 2019, Smoak should've had a .367 wOBA. That's a whopping 40 points higher than his actual wOBA.

To put that in perspective, his expected rates put him in the neighborhood of the actual results of Bryce Harper and Joc Pederson. But his surface numbers put him more in the production range of big disappointments like Paul DeJong and Dexter Fowler. Sure, they're about league average. But, Smoak is a well above league average hitter. As he has since been signed by the Milwaukee Brewers, apparently their front office feels the same way.

Going into his age 33 season and free agency, Smoak could be a really nice bargain. Of course, Smoak is also the exact type of player that teams are shying away from. With all the young talent Toronto is stockpiling, it was a foregone conclusion he wouldn't be back with the Blue Jays in 2020. The Brewers, on the other hand, are happy to guarantee him just $4 million for 2020, plus an option for 2021 at $5.5 million with a $1 million buyout.

It's likely no surprise that people aren't too excited about Justin Smoak rookie cards. He also doesn't have a Bowman Chrome Auto, which makes his card market a little harder to gauge relative to his peers. His top rookie autos are several 2008 Razor cards and 2008 Upper Deck Team USA. Of course, the Upper Deck cards are more sought after. For base rookie cards, there are the serial numbered 2010 eTopps and 2011 Topps rookie cards.

Because of his poor surface numbers, particular Smoak rookie cards don't sell that consistently. But if you are looking for one card to target, it would be colored refractors of his 2011 Topps rookie card, as those are the cards targeted most consistently.

A strong 30 HR and 100 RBI could still be in Smoak's future. While Milwaukee isn't a big market, a strong season from both him and the Brew Crew could help the value of Justin Smoak cards. What do you see in the cards (pun intended) for Justin Smoak's future?

by R.A. Rowell; Co-Owner ofIntent-sive Nature & theBrand Shamans network

I'm personally a BIG fan of the Topps Heritage product. While it may not have the big hits of Bowman Paper & Chrome, the card designs are classic and the sets have some fairly nice rookie cards. I've had my eye on the 2014 Xander Bogaerts High Number Rookie Card #H550 for a little bit. 

In early August 2019, this High Number rookie card had a PSA 10 pop of 189 and was selling for $20 to $25, with a high of $34. Raw, they sold for $10 to $15 like nuts on eBay! Interestingly, there are only 36 graded by BGS - one graded BGS 9, 31 graded BGS 9.5, and 4 graded BGS 10. But, by late August, there were only a few raw sales around $10 and very few of the PSA 10s were being listed. The only ones you’d find listed were anywhere from $60 to $75!

With Bogaerts easily one of the best, if not the best, current shortstop in the game, it's no surprise that people flocked to grab this affordable rookie card. Clearly, people decided to hold onto their copies. I expect PSA will grade more than a few of these before 2019 is out and with Bogaerts’ superstar play, it’s likely this will be the next of his rookie cards to see solid gains. 

The other of  Xander Bogaerts’ more popular rookie cards as far as grading is his 2012 Bowman Prospects card and its Chrome counterpart, both of which have exploded in price since June 2019. There are 159 PSA 10 graded examples of the Bowman “Paper” Prospect card. But, for some reason, I can’t find the population of the Chrome cards - PSA apparently omitted it from its POP report for that set. What I can say that the same card has 204 BGS 9.5 Gem Mint examples from Beckett, so the PSA pop of the Chrome card could be higher than its paper counterpart.

Anyway, the Chrome PSA 10 shot from about $20 shipped to $50 shipped in roughly a month. Now, that card is about a $70 example. Likewise, the graded “paper” card shot up from about $15-20 to over $40. Of course, the autographs are the more sought after cards, and they carry a $200-250+ price tag. That’s why the non-auto is so attractive, because of the significantly lower price point.

Topps Heritage High Number is not going to have nearly the same print run as something like 2012 Bowman and Bowman Chrome. So, it’s possible that the High Number Rookie Card could be an attractive long-term investment. At the very least, it’s a great rookie card of a Red Sox star with great eye appeal and a vintage feel.

What’s your favorite rookie card of Xander Bogaerts?

by R.A. Rowell; Co-Owner of Intent-sive Nature & the Brand Shamans network

Many baseball card collectors consider the 1963 Topps #553 Rookie Stars card to be a Willie Stargell rookie card. While that is absolutely true, the legendary Pittsburgh Pirate shares his rookie card with three other outfielders. As is the case with many early rookie cards, Hall of Fame ballplayers share their cards with lesser names. But, since these guys share a Rookie Card with a Hall of Famer, why not see how their careers turned out?

Brock Davis was certainly never a star at the MLB level. In fact, he’d only get into 242 games over parts of 6 seasons, amassing a whopping 0.2 WAR over that time. He carried a decent .331 OBP in his career, but had only one home run and not much else.

Jim Gosger never had much of an MLB career, although he hung around for parts of ten seasons. His 1963 debut with the Red Sox was a dreadful 19 plate appearance cup of coffee. Gosger actually wouldn’t resurface in the Majors until 1965, when he wasn’t a star but instead a league average hitter who gave the Red Sox 1.4 WAR in only 81 games. He would be perfectly acceptable in 1966 as well, but he’d be traded midseason to the Kansas City A’s with a couple other players for three players, including Jose Tartabull, who would be awful for the ‘66 and ‘67 Red Sox. (Tartabull’s son Danny would be a decent player, though). Gosger would carve out a basically replacement level career as a reserve outfielder. He was definitely NOT a star, with a career total of 2.3 WAR!

John Hernnstein is the worst player here, amassing NEGATIVE -2.0 WAR in his short career, 239 games over parts of 5 seasons. Not much to say about him other than he hit 6 home runs in 1964 for a Phillies team that had no business playing him in 125 games.

Meanwhile, this Willie Stargell fellow would amass 57.5 WAR over 21 seasons all for Pittsburgh. He’d hit .282/.360/.529 for an .889 career OPS (147 OPS+). He also hit 475 home runs. While he was a below average defensive outfielder and first baseman according to TotalZone, Stargell was easily a Hall of Fame player.

Considering the other three guys COMBINED for 0.5 WAR, I think it’s safe to say this is a Willie Stargell rookie card with three random guys. (Although, one is a Red Sox player so it counts for my Red Sox collection, which is funny to say!)

Super Bowl 53 belonged to the New England Patriots and Tom Brady, but a major part of the Patriots success came from Super Bowl MVP Julian Edelman. The wide receiver joined the New England Patriots in the 7th round of the NFL draft after playing quarterback in college. Since then, he’s become one of Brady’s favorite targets and his talent was on full display in Atlanta as the Patriots beat the Rams 13-3.

Obviously, being Super Bowl MVP is a big deal, so Julian Edelman rookie cards became a hot commodity right away as his MVP award was announced. Cardboard Connection has a great list of the top Julian Edelman rookie cards. But, if I had to pick one, I would certainly pick the 2009 Topps Platinum #159.

With only 8 PSA 10 copies in existence, the Julian Edelman Topps Platinum Rookie Card has room to grow. The day after the Super Bowl, raw copies of this card were receiving bids exceeding $40. It’s a nice-looking rookie card and the Topps Platinum Edelman RC has a refractor version, as well as a white refractor, and a platinum refractor numbered to 1549.

Juan Soto was quite the rookie sensation in 2018 for the Washington Nationals. With his strong on-base skills and plus power, he would’ve been the 2018 National League Rookie of the Year if not for Ronald Acuna Jr. With anticipation for a strong 2019 season and beyond, Juan Soto rookie cards are an extremely hot commodity in the baseball card hobby.

Here are five of the hottest Juan Soto rookie cards based on eBay auctions.

#5 - 2016 Bowman Chrome Juan Soto Rookie

Despite not being numbered, a raw 2016 Bowman Chrome Juan Soto Rookie Card with autograph was bid up well north of $400. A BGS 9.5 copy sold for $799 on January 20, 2019.


#4 - 2018 Ultimate Leaf Draft Juan Soto Rookie Auto 1/1

It’s always fun to watch what one-of-one sports cards sell for at auction. This rookie auto from Ultimate Leaf Draft fetched less than you’d think, under $150. If this is a card that interests you, there are other parallels numbered to 25, 15, 10, and 5.

#3 - 2018 Topps Update Juan Soto Rookie GOLD RC SP /2018!!!

While there are technically 2018 copies of this card out there, it’s rare enough that this raw card is getting bids in excess of $50. It’s a nice looking card.

#2 -  2018 Topps Gold Label Framed Juan Soto Nationals RC Rookie AUTO

This special framed Topps Gold Label card is available only through redemption - you can’t pull it from a pack. Of course, this makes this card a bit rarer than most, although these aren’t serial numbered. Despite getting quite a few bids, because it’s a bit of an oddball card, it will be interesting to see what sort of price this redemption rarity gets.


#1 - 2018 TOPPS CHROME UPDATE Juan Soto RC ORANGE AUTO REFRACTOR #17/25

This orange parallel refractor in 2018 Topps Chrome Update sold for four figures on January 20th, 2019 with a sale price over $1200! It’s one of the nicest looking Soto rookie cards out there, so there’s no surprise that this highly sought after card is causing a bidding war..

On May 24th, 2018, card collector Adrian Proietti bought a PSA 10 Derek Jeter rookie card from PWCC through eBay for $99,100. This Derek Jeter card is from the highly sought-after 1993 Upper Deck SP set. Ironically, Adrian was offered a similar card, also PSA 10, ten years ago for $25,000, which he turned down. While that price sounds extremely high, it came only a week after another Derek Jeter rookie card sold for $54,576. At nearly $100,000, Adrian’s purchase was the highest price ever paid for a modern baseball card. With Derek Jeter a likely shoo-in for the 2020 Hall of Fame class, just how high will Derek Jeter rookie card prices go?

Sure, other modern-era sport cards have fetched higher prices, but they’re in basketball and football. You may have heard of LeBron James rookie cards and Tom Brady rookie cards selling for hundreds of thousands of dollars. They, too, are graded by PSA/DNA, the leading card grading company in the world. Beckett Media also has a highly-regarded grading system, known as BGS. There are a few other grading companies, but none are as highly regarded. When graded and authenticated by PSA or Beckett, cards always fetch a higher price than ungraded "raw" cards.

For those unfamiliar with card grading, a PSA Gem Mint 10 or BGS Pristine 10 is the best you can get, a perfect example of a card in perfect condition. There are very few 10’s of any given card. At the time of the $99,100 sale, there were only 22 PSA 10 Derek Jeter rookie cards in existence. PSA said that they had graded 560 as a 9, or mint, and over 8000 graded as an 8, or near-mint. The SP foil rookie card of Derek Jeter is particularly tough to get in high grade as foil cards tend to show wear and/or damage far more easily than nonfoil cards.

While the differences between PSA 8, PSA 9, and PSA 10 may not be obvious to casual observers, they make a huge difference when it comes to collectible value. This makes sense because, of course, who doesn’t want their collectibles to be in perfect condition? There are also just so few cards worthy of a PSA 10, which is what makes them so rare. Even cards pulled straight from packs and immediately stored in a soft sleeve then hard plastic sleeve (also known as a top-loader) often grade as an 8 and sometimes a 9.

The only things that determine the price of graded cards are the scarcity of a given graded card and how much someone is willing to pay for it. Graded vintage baseball cards have been selling for big numbers for years, even those PSA 7 and below. But with how many cards are being printed today, grading is really the way to distinguish one card from another. Grading has always made cards valuable, and now they’re more valuable than ever.

So, just how high will the prices go on graded rookie cards? Even rookie cards from the “junk wax” era of baseball cards from the late 80’s to early 90’s are worth a few bucks if they’re graded highly. But the 1993 Upper Deck Baseball SP set is far from being a junk wax set. Sets since then have continued to have lower print runs on purpose to make the cards purposely more scarce. With a resurgence in baseball card collecting and sports card collecting in general, we could be seeing rookie cards of other stars start selling for six figures.

Unsurprisingly, there was a bit of a run on this particular card, but there are still fine examples out there for sale if you have the cash. You can find similar Derek Jeter rookie cards, graded and otherwise, for sale on Amazon.  

Who do you think will have the next high priced rookie card?

Luis Polonia was a journeyman outfielder/designated hitter who is best known for his time with the Oakland A's, Los Angeles Angels (then known as the California Angels), and three stints with the New York Yankees. He also played for the Atlanta Braves, Baltimore Orioles, and Detroit Tigers. One major highlight of Polonia's career was when he was traded to the Yankees by the A's to reacquire future Hall-of-Famer Rickey Henderson. (That one worked out better for the A's.)

Polonia was actually a very good contact hitter who didn't strike out much and would take walks occasionally. He also had a lot of speed and stole 50 bases twice, although during his best stolen base years he also lead the league in times caught stealing, as well. The one downside to Polonia was that he was not a very strong fielder. In fact, TotalZone has him at 57 runs below average on defense in his career.

But for a guy with a .293 career batting average and 321 stolen bases, Luis Polonia was a useful player. On baseball cards, we don't care about defense. We just want to remember his strong points. So, are Luis Polonia baseball cards worth anything?

Luis Polonia's first baseball card is from the 1984 T&J Sportscards Madison Muskies set. It's extremely rare. Terry Steinbach and Tim Belcher are the only other future Major Leaguers of note from that set. An easier one to find is the team-issued 1985 Team-Issued Huntsville Stars Burger King pre-rookie card. The set is best known for its Jose Canesco card. Polonia's card is worth between $0.50 to $0.75. It's not worth much, but for a serious collector of pre-rookie cards of long-term Major League ballplayers, it's worth having. Another pre-rookie card is the 1988 ProCards Tacoma Tigers #638. It's a bit hard to find.

The more valuable Luis Polonia rookie cards are the 1988 Score Rack Pack Young Superstars #22 and the #24 card from the 1988 Topps Toys R Us Rookies Box Set. If you're looking to collect Oakland A's rookies, these are the ones that are probably the best to collect.

Other interesting Luis Polonia baseball cards include:

1988 CMC Tacoma Tigers #16
1993 King B Discs Square #7 (Very Oddball!)
1993 Pacific Beisbol Amigos #2 w/ Stan Javier
1993 Pacific Spanish Prism Inserts #19
1995 Pinnacle Artists Proofs #445

While not every baseball card collector will be interested in Luis Polonia cards, there are definitely those out there who would be happy to have his rookie cards and rarer oddball cards, as well. He was a good hitter at the plate and burner on the basepaths who unfortunately gave away a lot of his overall value in the outfield. While his cards aren't necessarily great investments, they are definitely inexpensive additions to the serious team collector or rookie card collector.