Archive for pitch type linear weights

I have been toying around with an idea for pitcher-hitter match-ups based not on prior head-to-head performance or platoon splits, but rather pitch type linear weights.

For those that are unfamiliar, pitch type linear weights basically takes a batter or pitcher’s performance on each type of pitch they throw or face during the year (e.g. four-seam fastball, slider, etc.) and converts that performance into runs created or runs saved relative to average. At FanGraphs, we show both the total runs created or saved for each pitch (e.g. wFB) and a normalized version for the value per 100 pitches thrown (e.g. wFB/C).

I thought it would be interesting to compare the starting pitcher’s pitch type linear weight performance against the lineup he is facing. To do this, I calculated the difference in run value between each pitch type for each starting pitcher and the hitters they might face. The difference is shown in the tables below. Green coding denotes an advantage to the pitcher, while red indicates an advantage for the hitter. I used the normalized version of each pitch type (i.e. run value per 100 pitches thrown/faced) to control for playing time, pitches seen, etc.

The tables below show the match-ups for tonight’s game between the Marlins and Phillies (7:05pm EST) for both Josh Johnson and Roy Halladay:

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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.

Late to the party as usual, for the past few weeks I’ve become more and more interested in pitch-type linear weights for hitters.* In particular, I was curious as to what they might reveal about which hitters are particularly good at hitting particular kinds of pitches. For example, we sometimes call certain hitters “fastball hitters.” I’ve heard one of particular minor leaguer who shall remain nameless who hasn’t been called up because he allegedly has a “slider-speed bat” (given the dearth of other players in that particular organization that can hit the slider, you’d think that would be seen as a good thing…). And so on.

I thought that it would be interesting to look at differentials in linear weight values between pitches for different hitters. I found some interesting stuff, but I want to avoid the illusion than pretend that I’ve “discovered” anything at this point, so I’ll begin with a post (or two) about an individual . In the spirit of Dave C.’s earlier “questions” posts, this is the beginning of a conversation (and I hope to get more in-depth later) rather than the conclusion of a study. For today, I want to talk about Jimmy Rollins‘ recent problems against the fastball against the backdrop of his continued success against changeups.

* If you haven’t already read Dave Allen’s clear and excellent explanation of how pitch type linear weights work, I strongly recommend that you do so.

While Rollins is still a good player overall, there’s not denying that 2009 was a down year offensively, as he put up a mere .316 wOBA after a very good .357 in 2008 and an excellent .378 in his 2007 MVP campaign. This is well known. There could be different reasons for it (which may all have roots in age-based decline), for example, bad luck on balls in play. But what also stands out are his pitch-type linear weight values against fastballs and changeups.*

* Those of you who dutifully read Dave’s article already know that the linear weights are by count, there is the chance, of course, that recently Rollins is only falling behind on fastballs then crushing them later, but that seems pretty unlikely, and for simplicity we’ll be ignoring that possibility for now.

Over the last three seasons (2007-2009), Rollins has been +6.3 against fastballs, and +22.8 against changeups during the same period. As one might expect, during that time his best season against fastballs was 2007, when he was +10.7. He was even better in 2006, at +20.4. However, he’s been in (apparent) decline against fastballs since 2006 and 2007, sporting a -1.8 in 2008 and a -2.7 in 2009. His rates per 100 fastballs bear out the decline as well: from 0.58 in 2007 to -0.12 to -0.17.

In contrast, Rollins continues to be consistently good against change-ups. While prior to 2007, his numbers against changeups where generally unimpressive, in 2007 he smashed them for +13.3, and while he hasn’t been as good (against much of anything) since then, while he numbers against fastballs dropped off, in 2008 he was still +4.5 (+1.29/100) against changeups, and in 2009 +5.0 (+1.36/100). More interestingly, of the good hitters I looked at (bad hitters are terrible against most everything), Rollins had one of the biggest “gaps” in his numbers between fastballs and changeups. I’m curious as to what this means.

Obviously, players typically lose ability as they age, but I’m curious if the linear weights tell us something specific about how that works for hitters. I apologize for ending with questions, but that’s better than presumptuous answers. I want to know if readers a) have any insight (even educated guesses) into what’s going on with Rollins in particular and/or b) want to see more stuff on this. Is Rollins “sitting changeup” more often as he gets older? Maybe, I don’t know for sure from the data I have. It would be easy to say he’s doing this because he’s aware that he’s “lost bat speed,” but to me, that is also a leap — “bat speed” is a useful scouting term, but it is too quick to infer anything about that that from the data I’m looking at. Perhaps an aging study can be done down the road using this or other data. I don’t know what this means right now, but I’m interested to see if we can find out.