In the last few days here on AN, there's been quite a bit of discussion about the intersection between luck and skill as it applies to the team as a whole. Don't worry, that's not what I'm here to talk about... I'm here to talk about it at the individual level! Specifically, Drew Pomeranz has been just one more example of (relatively) good process leading to poor results.
Pomeranz has gotten a lot of grief so far this season, and understandably so: the results just haven't been there, to the tune of a 4.66 ERA. If you look at that ERA and think that's pretty bad, you wouldn't be wrong. But there's a bit of evidence that while the results haven't been there, Pomeranz has been suffering from some... brace yourselves... bad luck.
The first place to look when a pitcher has an ERA that seems out of proportion with how they've performed in the past is to look at their FIP. FIP stands for fielding-independent pitching. The theory behind FIP is that once a batter puts a ball in play, there's little the pitcher can do to control where it goes and whether his defense can field it. Thus, FIP only measures the things that the defense cannot impact: walks, strikeouts, hits by pitch, and home runs. While you might see some holes in the theory, FIP has been extensively back-tested and it has a much stronger correlation with future performance than a pitcher's current ERA.
While Pomeranz has an ERA of 4.66, his FIP is nearly a run lower at 3.78. While not great, it's not disastrous either. While the eye test might tell you otherwise, the main driver of his lower FIP is his 6.8% walk percentage, the lowest it's been since he reached the majors. Control has always been Pomeranz's biggest knock against him, and the numbers show that he's been much better in that area this season.
The much bigger driver of his ERA, though, have been the results once runners have gotten on base. I strongly encourage you to read Fangraphs' rundown of LOB% (also known as Strand%), which explains the theory of whether pitchers can control the sequencing of their hits: whether they're more or less likely to give up hits with runners already on. At this point, there's next to no evidence that pitchers have any control over it.
As such, the league-wide LOB% is consistently 70-72%, and pitchers have shown little ability to consistently stay under or over it. In other words, if a pitcher has an LOB% well above 72%, they are standing an inordinate number of runners and their ERA is likely to go up in the future as that LOB% regresses. The opposite is true for a low LOB%.
Drew Pomeranz? Welp. His LOB% is currently 54.3%, good for dead last in all of baseball. In other words, Pomeranz's ability to hold runners again (for which, as noted above, there's no evidence) has been the worst in the whole league. I'll leave that up to you to decide whether that's bad luck (full disclosure: put me squarely in that camp) or some sort of unclutchiness on the part of Pomeranz.
While Pomeranz process has by no means been great this season, there's lots of evidence that he's not the trainwreck that his ERA might suggest, either. Expect some regression- the good kind! - from him moving forward.
EDIT: If you want to read MORE about Pomeranz's lack of luck, please see MehranTheGreat's excellent piece from last week in the fanposts!