The Baseball Graphs Blog

The Curious Case of Mike Gonzalez

Last week, I posted an article at the Hardball Times called Ranking the Relievers. In it, I presented a stat I had calculated called WPA (Win Probability Added) to measure how much each reliver had helped his team win. I won't go into the details here, but I urge you to read if you haven't already.

Rich Lederer sent me an e-mail, asking why Mike Gonzalez didn't show up on the list of WPA leaders. Good question. Gonzalez had a fine year in 2004, with a 1.25 ERA in 43.1 innings, including 55 strikeouts, 6 walks, 32 hits and 6 home runs allowed.

Here's my e-mailed reply to Rich:

Believe it or not, Gonzalez only had a WPA of 0.294.

Out of 49 appearances, his WPA went down 15 times, which is surprising given his stats. He particularly had a terrible June.

In one outing against the Reds in June, he came in with the bases loaded, a two-run lead and two outs in the 7th and gave up a grand slam. -.638 WPA

Five days before, he had come in against the Mariners in the seventh, runners on first and second, one out, scored tied and gave up two runs. Neither was credited against him. WPA of -.427

His highest "leverage" appearance came on the 5th of June against the Cubs: bases loaded in the 7th, up by one. Gave up a sacrifice and base hit, allowed all three runs to score (none credited against him). WPA of -.340

His best WPA was 0.264, in May against the Padres (his first appearance of the year). One on, one out in the 6th, he pitched one and a third innings of scoreless ball and didn't allow the run to score.

He did well in lots of other appearances, but they tended not to be high leverage ones. Pretty interesting case study.

The bottom line is that Gonzalez did a fine job, but not usually when the game was on the line. It's a great example of what you can learn from a stat like WPA.