The defense behind him, more than anything else. He's only allowed something like 33 hits in 57.1 IP. Yeah, his K rate, BB rate, and HR rate (and HR/FB) are all pretty comparable to his prior Cubs experience. Its just that coming into todays game he has a 203 BABIP, resulting in a 173 average against. Granted he has only allowed a 14.6 LD%, but thats not really a skill and will regerss to the mean. Regardless of what his ERA says, his underlying statistics show that he was and is a league average pitcher. There's still some interesting digressions from his previous Cubs career that shouldn't be dismissed out of hand. 1) There is a noticeable difference in his pitch selection. He's throwing more fastballs at the expense of sliders. 2) All three of his pitches are coming in at a consistent 2 MPH below when he was a closer, possibly indicating a change in the way he's pitching. 3) Not only is his LD% lower, his FB% is as well, with the difference all going to his GB%. If he was just getting LD-lucky, I wouldn't imagine the difference would be that pronounced. http://www.fangraphs.com/statss.aspx?playerid=517&position=P He's nowhere near as good as his ERA, and I don't know if any of this will be meaningful long-term, but it's curious to say the least. RE #1 I'm guessing this has to do with him having to "conserve" his slider. When you are facing batters multiple times as a starter vs once as a reliever, you have to not show all of your pitches the first time around. I'm guessing this is just correlational with moving to the starting role, rather than a causation for his success. If anything, you would assume that a pitcher who does a worse job at randomizing his pitch selection will get hit harder. RE #2 I'm guessing the reduction in speed can be attributed to the fact that he was only pitching one inning at a time before and could go all out and is now pitching multiple innings and needs to conserve himself and/or get tired later into games resulting in a slower average than when he was closing. RE #3 Yes, his GB% has increased, and hes eclipsed the point where GB% becomes moreso due to skill than luck (ie r^2 exceed 0.5) of 150 batters faced. Thats great an all, but on the flip side that further exposes the luck in his BABIP. Fly balls get converted into outs more than any other type of batted ball, and even though he has a really low BABIP, he has a low FB%, meaning that his BABIP should actually be higher than our standard LD%+.120 estimation (because those non-line drives are mostly ground balls (infact 2:1 in comparison with FB), which are turned into hits much more often than FBs). Ok, he's not going to finish the season being top 3 in cy young voting. I don't think anyone thinks he will. I, and I know I wasn't alone in this, was worrying about the guy giving up 85 runs in 150 innings for the season. He'll get worse, but that much worse?