Fastballs Are Pretty Important

As we begin the 2010 season, I’d like to take yet another (brief) look at something from 2009. If you’re here, you probably know that three young American League pitchers took big steps forward last season: Justin Verlander, Felix Hernandez, and the 2009 AL Cy Young winner, Zack Greinke. While all thee had good seasons in 2008, they each had a monster season in 2009. Their individual paths to greatness has been much chronicled here and elsewhere. But while browsing through some player pages recently, I noticed something all three had in common as they moved from 2008-2009: the effectiveness of their fastballs.

Some of my friends who are Tiger fans have said that Verlander had a down season in 2008. I don’t agree, and neither do FanGraphs’ win values, having Verlander’s 2008 in line previous seasons at 3.4 Wins Above Replacement, and his FIP was the second best of his career to that point. 2009 went far beyond that, of course, with Verlander sporting a 2.80 FIP and an 8.2 WAR. That’s a monster season. This is, again, well-documented, and I’m sure that there are pitch f/x experts, scouts, etc. that could give you an account of what he did differently. Numerous stats improved for Verlander, as well. But for now, the one that stands out to me is in Verlander’s pitch type linear weights. With the exception of a +13.3 season in 2007, Verlander’s fastball had been about average prior to 2009. However, in 2009, coming off of a +0.4 season with his fastball in 2008, he put up a +24.3. He threw his fastball a bit more often, but it wasn’t just quantity. While his slider and curveball were less effective than they had been in 2008, per 100 pitches, his fastball linear weights rose to 0.96 from 2008’s 0.02 (his changeup was also more effective).

King Felix’ ascension to his throne had been long-awaited. That’s not to say that his series of ~four win seasons from 2006-2008 weren’t very good for a very young pitcher, but 2009 was a new level — an extremely impressive 6.9 WAR outing. In 2006 and 2007, his fastball was actually below average (according to pitch type linear weights, which is different than a pitch f/x or scouting analysis, I’m not saying his fastball was “bad” during those seasons). In 2008, he began to through his fastball more, and it was +6. In 2009, he threw it almost as much, and to greater effect, +19.0, although all his pitches improved per 100 over 2008.

It was Greinke’s number that started me down this path. Everyone knows about Greinke’s 2009, but he was also the best of these three according to WAR in 2008, with 4.9. 2009 was one of the best seasons by a pitcher in the FanGraphs era, at 9.4. What was surprising to me was that in his excellent 2008 season, his fastball was below average, and this was true of all of his other seasons in the majors other than 2007, much of which he spent in the bullpen. Through 2008, his slider had been his most effective pitch (by linear weights). In 2009, as one might expect from the overall improvement, all of Zack’s pitches improved, including his devastating slider and so-so change, but none more than his fastball. Whereas his fastball was only -3.8 in 2008, in 2009 it was +25.8, and he actually threw it a bit less frequently.

Other pitchers could be discussed here, for exampe, Florida’s Josh Johnson, whose fastball was +4.7 in his 2.0 WAR 2008, and +21.5 in his 5.5 WAR 2009. Of course, Greinke’s 2008 season indicates that some pitchers can have great seasons without their fastball being that effective (by count). Johnson’s teammate Ricky Nolasco improved from 2008 to 2009 despite his fastball linear weights going from +4.7 to -15.5 — his slider was awesome in 2009. Again, scouting and pitch f/x has much more to tell us why and how these things happened. And keep in mind that the linear weights are by count, so pitcher could be changing their sequencing and other things that we can’t see directly from the linear weights.

But I find this interesting nonetheless. Hence, my groundbreaking thought for the day: the fastball is an important pitch.