Thus far, I've had a pretty difficult time unpacking all of the stuff that we've seen from Charlie Morton in his four starts back from Tommy John surgery. His ERA (2.50) looks great, but he's given up an alarming number of unearned runs (six of the 11 runs he's allowed have been unearned) given that one of the league's best defenses plays behind that unbalances that a bit. Still, he's been pretty good about keeping runners off of the bases -- his walk rate is lower this year than it was in 2011 and he's giving up fewer hits per inning than at any other point in his career. That would seem to indicate that the weird amount of unearned runs is at least partly bad luck.
Before his injury, Morton was experimenting with a cutter because lefties were absolutely crushing his fastball/sinker. He hasn't thrown one cutter this year and he seems to be relying on both his four-seamer and his sinker much more than in the past (he's still throwing his changeup and curveball, but less so than in 2011 or 2012). Still, he's still holding lefties to an OPS below .700 this year. He's walked quite a few lefties thus far, but other than that they haven't been nearly the same problem for him that they've been in the past. I suspect that that has something to do with his increased velocity post-surgery.
All of this is to say that even though he's been occasionally frustrating this year, I think it's fair to say that he might be due for a strong start if the defense gives him some help. Obviously facing the Cubs provides that opportunity. He'll face off against Edwin Jackson today. I think the Pirates have faced Edwin Jackson in approximately 50% of their games this year. The first pitch is at 4:05