Slider Location Based on Platoon Split

Sliders are a heavy platoon pitch. The traditional pitcher will use the slider when they have the platoon advantage and go to the changeup when they do not. The numbers make it clear that this is the best approach (it is also a big reason why pitchers who throw mostly sinkers/sliders don't succeed very often as a starter). However, a discussion between Eno Sarris, Dave Cameron, and Marc from USSMariner prompted me to look at pitchers who move or don't move their slider based on platoon. That is, do some pitchers who still like to throw their sliders without the platoon advantage throw it in a different location on average?

So I looked at pitchers that have at least 100 sliders (MLBAM tags) this season (I am only looking at 2013 data) against each lefties and righties. 100 is admittedly an arbitrary number, but it is few enough to include relievers, but hopefully enough that we get pitchers who actually it as a weapon against both lefties and righties. This gives us 60 pitchers, so here are their average locations against lefties, followed by righties, and then the standard deviation of both their average vertical and horizontal locations to give us an idea of how big the difference is. The following is the results, sorted by pitchers with the largest horizontal difference, meaning the ones who moved it the most by platoon.



Some surprises and some non surprises here. Bronson Arroyo being near the top is no surprise considering all of the weird things he does while pitching, and it wasn't surprising to me that a guy like Matt Moore was near the bottom. Several Yankees rate highly, which is interesting. Hughes and Phelps are homegrown, but Kuroda and Kelley are not, so it is hard to say that it is taught (though perhaps it is something they look for). The three Japanese natives rate highly, which I don't find all that surprising considering the difference in slider compared to the traditional North/South America slider. Ryu is right about in the middle interestingly (though he has a pretty traditional changeup he uses against righties).

Madison Bumgarner and C.C. Sabathia don't rate well, though their sliders are sometimes considered cutters. I thought it was interesting that Ervin Santana and Bud Norris didn't rate well even though they are starters that notoriously heavily rely on the slider. Yovani Gallardo's slider usage was recently called into question despite the lack of platoon splits, and I think we see why his platoon splits are not large. He locates the slider away no matter the platoon.

Some other notables include Alexi Ogando, who doesn't have a real sweeping slider, but has always used it frequently. His doesn't really change in location, and I thought Luke Gregerson, who reportedly has at least 3 sliders, would be closer to the top than he was.

I was surprised by how much difference there was on average, especially considering what we saw with the average whiff location charts. I guess it would stand to reason that pitchers who are more willing to throw the slider to both lefties and righties would have their sliders in different locations (or have slightly different sliders) by platoon. The horizontal difference was much more prevalent than the vertical difference, with some pitchers (such as Sale, Richards, and Miller) having no difference in vertical location of the slider.  

Free Agent Watch: Dontrelle Willis

During last off-season, the Reds signed Dontrelle Willis to a minor league contract. When brought up to the Majors, he gave the Reds a -.1 pitching WAR, and a 2.29 PE. For comparison, Madison Bumgardner had a -1.43 PE, Chad Billingsly had a .94, and Wade Davis had a 3.31 PE. As Willis was my example in calculating Throwing Rating, his TR was 8.81. For comparison, Bumgardner had a 13.05, Billingsly with a 8.88, and Davis a 7.52. This is not horrible or anything, but it is increasingly clear that Willis has lost whatever made him so great with the Marlins those years. However, he has some value elsewhere. He actually had a .7 WAR as a hitter (giving him a .6 WAR overall). He did this in just 34 Plate Appearances, that is .02 WAR per PA. Albert Pujols has a .008 WAR per Plate Appearance this season (in 2010 he had a .011 WAR per Plate Appearance), and Josh Hamilton had a .006 WAR per Plate Appearance (in 2010 it was .013, this is only using Offensive-WAR). Willis has a career 4.3 WAR in 447 PA, giving him a .0096 WAR per plate appearance. So the real question becomes: why doesn't Willis become an outfielder? It is probably impossible using fielding statistics to see his ability to field at outfield, one would just need a sample size of him out there. However, this is something that has been done before, and it has worked. The biggest example is Rick Ankiel. Ankiel had a .007 WAR per Plate Appearance before making the switch to the outfield. In 2011 with the Nationals, he put a 2.1 WAR season together. If we use that metric, then Willis would put up a 2.88 WAR season. He is a better hitter than Ankiel was when he was a pitcher. So far, Willis is a .244/.287/.665 hitter, but one would think that these would improve as he focused on being a batter. According to Baseball Reference, his 162 game average (he has had plate appearances in 244 games) would be 316 PA. If given full time playing time, he would get at least twice as many. This would give him (using his averages) 12 HRs, 56 RBIs, 60 R, .79 PPG, and a 3.55 PAPP. Again, one would think these would improve, and if they do, he could be a very solid 4th outfielder. Of course, Willis will have to choose this route, but I think it would be the best route for him, and he could be very valuable to a team.