Last night a perfect example of Joba the enigma

Earlier this season I investigated Joba Chamberlain‘s peripherals. When I had the idea for the post I thought I would discover an obvious problem in Joba’s numbers — too many home runs for example, or too high a walk rate. Instead, I was stunned to discover that Joba has actually improved his peripherals this season.

When I wrote the post Joba’s K/9 rate was 9.99, his BB/9 rate was 3.61 and his HR/9 rate was an excellent 0.64. All of these were solid improvements on his 2009 campaign, when he struck out only 7.61 batters per nine innings, walked an atrocious 4.35 batters per nine, and gave up a Javier Vazquez-esque 1.2 jacks per nine. Despite those improvements, at the time of the post his ERA was a mind-blowing 5.95, compared to 4.75 the year before. As I wrote at the time, the normal assumption is that a pitcher will improve his numbers if he strikes more batters out, walks fewer, and allows fewer home runs. Unless that pitcher is named Joba Chamberlain.

Since that post Joba’s numbers have improved further. Entering last night’s game he’d lowered his ERA to 4.34 and his BB/9 rate to an excellent 2.85, while keeping his K/9 and HR/9 rates relatively constant at 9.23 and 0.68, respectively. His solid peripherals show up in his FIP and xFIP. Despite the high ERA, Joba had a 3.02 FIP and a 3.48 xFIP entering yesterday’s ball game.

Sadly, peripherals are on the periphery because they don’t tell the whole story. Something has been wrong with Joba this season, even though he’s improved on so much of his game. His performance in the sixth inning was an excellent example of this. He didn’t walk anybody. He didn’t allow any home runs. Heck, he was only charged a single run, but he gave up two hits, two solid, soul-crushing, game-ending hits that the defense couldn’t run down, a mammoth double to B.J. Upton, and a back-breaking single to Carl Crawford.

Those two hits represent the reason Joba has been having a bad season, and the reason his bad season has been such a mystery. The dude got hammered, but he didn’t walk anybody. He didn’t give up any home runs. None of what he did will show up in any of the very relevant pitching statistics that I’ve mentioned so far in the post, except his ERA (and, sadly, CC Sabathia‘s), which went up. ERA aside, according to many of the statistics we use to measure a pitcher, Joba improved his season last night.

Like it or not, Joba Chamberlain represents a key component of the Yankees’ future. He’s a cost-controlled pitcher who has shown flashes of being a great reliever, and may yet find his way back into the rotation. If Phil Hughes‘ key problem is that he gives up too many home runs, then Joba’s issue is almost the opposite — he keeps the ball in the park, but the batter puts it some place three different fielders have to scamper to get it. Unfortunately for the Yankees, fixing this problem may prove to be difficult for the foreseeable future.