Mauer’s Splits by Dave Cameron February 8, 2010 There are a lot of interesting tidbits of information that can be gained through the new splits pages found here on FanGraphs, but there is one that shines above all the rest – Joe Mauer. The Twins star catcher is not just a tremendous hitter; he’s also a tremendously weird hitter. Take, for example, Mauer’s career spray chart numbers for balls hit to different areas of the field. There are a few things that should jump off the page immediately. How about that crazy 10.09 GB/FB ratio when he pulls the ball, which is the result of that even crazier 7.6% FB% on balls to right field. Seriously, seven point six percent of his balls to right field are categorized as fly balls. When Mauer turns on a pitch, he’s beating it into the ground. That flips entirely when he hits the ball the other way, though, as nearly 50% of his balls in play to left field are fly balls. That latter number is entirely normal, actually – it’s the batted profile on pulled balls that is so nutty. Actually, for reference, let’s just give the league averages for all hitters on their spray chart data. That’s the norm. You’ll see the obvious pull power, with both LH and RH hitters posting .280 ISOs when they hit to their pull field. That gets cut in half when a normal hitter goes up the middle or the other way. For pretty much every hitter in baseball, their lowest wOBA is going to be to the opposite field, where fly balls are high but home runs are low, leading to a lot of weak fly outs. Mauer, though, is no normal hitter. His power is almost entirely to left field. When he goes the other way, he runs a .410 wOBA, and his ISO is twice as high to LF (.257) as it is to RF (.122). When he pulls the ball, he’s pretty terrible, posting just a .289 wOBA, thanks to the copious amount of ground balls. The difference between his pull/opposite field numbers are stunning, especially in comparison with how pretty much every other hitter on earth functions. In fact, given this data, there’s actually a case to be made that teams should consider employing two different shifts against Mauer; an outfield shift playing him as if he was a pull-heavy right-handed batter, and an infield shift treating him as a pull-heavy left-handed hitter. Groundballs to the left side and flyballs to the right side comprise such a small percentage of Mauer’s batted ball profile that a straight-up alignment is an inefficient way of defending him, and he’s made a living by taking advantage of it. If you employ the traditional infield shift, with three defenders on the right side, you should be able to limit his hits through the hole from the crazy amount of grounders. At the same time, shifting your outfielders the other way, shading towards left field, will cover more of the areas where he traditionally racks up his extra base hits. By having the outfielders shifted towards left, you’re also more likely to cut off balls that roll past the third baseman, who is left to defend that side of the infield by himself, before they get to the wall. It would look really weird, and Mauer’s a good enough hitter that he may just render the whole thing moot by changing his swing and swatting balls to the right field corner, but I’d love to see a team give this a try. The current way of trying to get him out certainly isn’t working, and his batted ball profile is so unique that it almost demands a radical change in how you position your fielders when he’s at the plate. So, stat guys working for MLB clubs reading this, this is your challenge for 2010 – convince your manager to give the double-shift against Mauer a chance. Make him change his approach in order to get on base. Stop letting him beat you just because he’s so different than a normal hitter.