Any time a player performs badly, we all line up to explain why. The explanations vary, but one of the most controversial ones involves the word "luck". And since we've been having this conversation about Joba for most of the season, perhaps I should take some time to elaborate on exactly how he's gotten unlucky.
Read this with an open mind. Sometimes things aren't what they seem, and sometimes we're too quick to rush to judgment and lean too heavily on arguments that we'd like to be true, even though they're based on dubious logic and little factual evidence.
Joba has a phenomenally low HR/9 rate (0.6), and has pitched with the bases empty 43% of the time this season. Yet every single home run he's allowed has come with runners on base. One even came with the bases loaded. Compare to Chad Gaudin, who allowed 14 home runs last year, 11 of which were solo shots despite the fact that he had runners on base 46% of the time. I won't discount the human element - lack of focus, nerves, etc. - entirely, but come on! If anybody had enough focus and control to keep the ball in the park at will, shouldn't he allow zero home runs?
Chamberlain also ranks in the top 8% of MLB pitchers in K/9, and the top 30% of pitchers in swinging strike percentage (translation: he's an above-average strikeout pitcher), yet when opponents do manage to make contact they're somehow hitting .399 off of him this season. Not even Kei Igawa allowed a .399 BABIP. Kei Igawa! If Joba's pitches are fundamentally flat and hittable, why are opponents swinging and missing at it so often? Shouldn't they be clobbering them all of the time, instead of striking out every fourth plate appearance?
To add insult to injury, 14% of the earned runs he's "allowed" (4 out of 28) actually crossed the plate when another pitcher was on the mound. Sure, he put the runners there, but the pitcher who's on the mound when they score has to bear some of the responsibility, doesn't he?
Joba has absolutely no control over the precise time he allows a home run, nor can he control what Damaso Marte, Mariano Rivera, or any other pitcher after him does. Let's suppose in a parallel universe that all of the home runs he allowed were solo shots and the pitchers who came in after him stranded those baserunners. It's not inconceivable. In that parallel universe, Joba has an ERA of 4.04, and we haven't even considered better results on balls in play (the Yankees are a solid defensive team this season). This is the crux of the "bad luck" argument.
He's throwing more strikes, striking more batters out, inducing more groundballs, allowing fewer homers, giving up fewer walks, hitter fewer batters, and tossing out fewer wild pitches, yet he still has a terrible ERA. He's improved in every single statistical category save for ERA, which is by far the one single category he has the least control over.
If you disagree with me, fine, but don't respond with "the problem is between his ears" nonsense. Instead, find me one pitcher in the history of baseball who has improved in all of those areas while simultaneously becoming a fundamentally worse player. I dare you