What has caused Paul Maholm to go from an ace in 2008 to a back-of-the-rotation starter in 2009? Why is his ERA a full run higher than it was last season? Let’s take a closer look at the numbers, courtesy of FanGraphs.
His strikeouts are down a bit, his walk rate is about the same and his homeruns allowed are down substantially. There is nothing in those numbers that would indicate that he should be considerably worse this year. However, his BABIP has jumped from a normal figure last season to one that is much higher in 2009. This is either the result of poor defense or bad luck. Considering the much-improved Pirates’ defense this year, I tend to think it is due more to random chance.
|Line Drive %||18.6%||18.9%|
|Ground Ball %||53.6%||51.4%|
|Fly Ball %||27.8%||29.7%|
Other than a slight increase in fly balls, there is not much difference in Maholm’s batted ball profile from last year. There is a dramatic difference in his home run per fly ball (HR/FB) rate. A normal rate is generally in the 10-12% range, and pitchers generally have little control over it. A pitcher can manipulate the number of fly balls he allows, but the hitter usually determines whether those fly balls carry over the outfield fence. Expect Maholm to allow some additional gopher balls as that number begins to regress toward a more normal percentage.
I do not have any great insight into these numbers, but I just wanted to point out that Maholm has leaned a bit more on his off-speed stuff this year. In addition, it is not shown in this post, but there has been no significant change in his velocity this year.
These numbers indicate that Maholm may not be fooling hitters as much this year. He is getting fewer swings-and-misses, and may be going out of the zone more often in an attempt to compensate. This will be something to keep an eye on as 2009 winds down and we move into next season.
These are the most important statistics to me. FIP is a fielding-independent metric, based on strikeout, walk and home run rates. Courtesy of StatCorner, tRA is also fielding-independent, but more specific and precise. As we you can see, both numbers have improved this season, despite the rise in ERA. This tells us that Maholm was lucky last year, whether that was due to defense, random chance or some combination. (You may remember that David Pinto’s Probalistic Model of Range showed that Maholm was aided significantly by his defense in 2008, at least considering the Pirates’ poor fielding behind most of their pitchers. It will be interesting to revisit this when the 2009 PMR numbers are released after the season.) This year has been just the opposite. Maholm’s peripheral stats, mostly his home run rate, are slightly better, yet he is allowing more runs. He is pitching just as well as he did in 2008.
Bringing it all together, here is Maholm’s value in Wins Above Replacement (WAR).
Maholm has already been worth 2.4 wins this year, nearly matching his 2008 value with two months left in the season. I think the real problem is that our expectations were too high. Maholm is a solid mid-rotation starter, but he pitches to contact and relies heavily on his defense and random chance. Because of that, his numbers are likely to fluctuate a bit from year to year. However, Maholm is still a major piece of the Pirates’ future.