When the Yankees announced they were bringing back Andy Pettitte yesterday the first thing a bunch of fans said was “now Joba can go back to the bullpen, where he belongs.” They said this when they signed CC. They said this when they signed AJ. It’s like clockwork. Luckily Eric Seidman at Fangraphs broke out some math and showed just how more valuable a starter is than a reliever.
Seidman shows that as a starter, Joba could pitch to a 4.10 FIP over 150 innings and be worth +2.6 wins. That’s a good but not great projection, and I suspect many Yankee fans would be a little disappointed with that kind of output out of the big Nebraskan. In fact, 51 starters put up +2.6 WAR last year, including guys like Wandy Rodriguez (+2.7), Dana Eveland (+2.7), Jesse Litsch (+2.8), and Ubaldo Jimenez (+4.4). The +2.6 WAR Starter club isn’t the most exclusive club in the world, as you can see.
Now, to match that production as a reliever Joba would basically have to be one of the five or six best relievers in baseball by putting up a 2.28 FIP in 80 innings, and even that only works out to a +2.4 WAR. Only eight relievers matched the +2.6 WAR Joba could reasonably put up in 150 mediocre innings as a starter, and they’re like, the eight best relievers in baseball pitching in highest of high leverage situations. Even the almighty Mariano Rivera, baseball’s most valuable reliever last year with a +4.2 WAR, was just the 26th most valuable pitcher in the game last year.
There really is no debate. Joba Chamberlain, even as a middling starter, is more valuable to the team than he is as a shut down reliever. Bringing Pettitte back doesn’t change anything, all it does is push Joba back to the fifth spot. This isn’t a situation like Mariano Rivera or Joe Nathan, where the guy doesn’t have enough pitches to start. There’s a reason guys become relievers, and it’s because they aren’t good enough to start.
Please, end the foolishness. Joba should be a starter until he proves he can’t handle it.