Yes, Rick has been a bit lucky this year. The fiery competitor only gave up 1.3 walks per 9 innings, which is the second best rate among starting pitchers in the Major Leagues in 2016. Interestingly, Josh Tomlin of the ALDS rival Cleveland Indians has the best rate. If you don't walk many people, you're not going to have a ton of people on base.
To be fair, having only a .269 batting average on balls in play is a bit low. It's hard to expect Porcello to continue being this lucky on would-be hits. Obviously, the Sox defense has something to do with this. Still his FIP (fielding-independent ERA) is 3.40 compared to his "actual" ERA (earned run average) of 3.15. Even then, he's still a 5-win pitcher, and the best on the Red Sox.
The only other thing that may be a warning sign is his expected FIP, which uses a normalized HR/9 rate. This brings his expected ERA close to 4, and hardly the caliber of an ace. But Porcello is still keeping the ball on the ground most of the time, as he has in the past. So it's possible that his home runs will be down going forward.
It's a great thing that the Red Sox kept their faith in Porcello after a rough first season. The five-year extension that he received is looking like a smart decision now. While it's hard to say if he'll replicate these numbers in 2017, this is the pitcher that the Red Sox were after before the 2015 season. Right now, with David Price not quite living up to expectations, Rick is easily the team's ace.