In 2005 and 2006, we would've all agreed that Zach Duke was a more promising pitching prospect than Paul Maholm. In 2007, we would've all put him behind Tom Gorzelanny and Ian Snell in the rotation. In 2008, Maholm was the only pitcher to emerge unscathed from one of the worst team pitching performances in team history and now in 2009 we're all expecting him to ace an improved staff. So what's happened to Maholm since 2005? And can he keep it up?
It's been interesting to watch Maholm progress as a pitcher. When he came up in 2005 and in his first full season in 2006, he walked far too many batters for a lefty without overpowering stuff. In '06, his 81 walks in 176 innings gave him a rate of 4.14 per 9 innings. His control improved in the second half of 2006, though, and in 2007 he only walked 49 batters in 177 2/3 innings (2.48/9 innings), which was an impressive improvement. That saw his WHIP drop from 1.608 in 2006 to 1.424 in 2007 and it was pretty clear that he was pitching better, even though his ERA went up. Last year his ERA went way, way down (to 3.71, a full run better than his previous full-year career low), but there's good news and bad news about that. His strikeouts reached a career high 6.06/9 innings and his walks stayed down, but his batted ball data didn't change much. He actually gave up more line drives in 2008 (18.6% vs. 17.1% in 2007). The big difference in 2008 was that the Pirates' defenses actually appeared to give some help to Maholm.
The only possible explanation that I can come up with for that is that Maholm had a much better ground ball/fly ball ratio than any of the other pitchers on the Pirates staff, all of whom were far more hurt by the Pirates' defense. Pinto's system ranked both Jack Wilson and Adam LaRoche as above average and the Andy LaRoche/Jose Bautista combo came in as about average third, while Nate McLouth, Xavier Nady, and Jason Bay all score very poorly. Given, again, that his line drive percentage went up, it seems pretty likely that Maholm got some unexpected help from the infield defense last year.
That's not to say that Maholm's not improving as a pitcher. In 2006, his K/BB ratio was 1.44. Last year it was 2.21. The increase in strikeouts and decrease in walks makes a big difference. FanGraphs has Maholm's FIP (fielding independent pitching, a method of approximating ERA using factors that only the pitcher can control) declinining from 4.81 in 2006 to 4.60 in 2007 and 4.15 last year. The Hardball Times sees a similar trend.
So while it's true that Maholm probably didn't pitch quite as well as his ERA indicated last year, he is getting better every year. The improvement in his strikeout and walk rates is plainly evident and since he's only going to be 27 in June, there's no real reason to believe he'll regress a lot in 2009. His ERA may drop back a bit towards the other side of 4.00, but if that happens it'll more likely be a case of him not getting as lucky with the defense. He's not a true ace and the fact that the Pirates are forced to treat him like one painfully spells out how bad the pitching situation is, but he is a solid middle of the rotation starter.