American League L/R Platoon Splits for Batters

You don’t have to have read The Book to know players generally hit opposite-armed pitchers better, though they do have a great, great chapter on platoon splits of all kinds.  This is something that makes sense to people on a basic level, even if you only have ever watched.  Pitchers tend to have an advantage, no matter the arm slot, when facing batters that bat from the same side, i.e. righty on righty or lefty on lefty.  This is why switch-hitters are so coveted and why your Dad made you take 50 cuts from the other side of the plate when you were 10, you know, just in case.

Since platooning is such a great way to take advantage of a roster I wanted to take a look at which teams are using and benefiting from the platoon advantage.  To give this any kind of context, we need to first develop a baseline.  Here are the AL average breakdown for each scenario as well as the wOBA so far in 2010:

Indirectly, you can do some easy math to find that right-handed batters account for roughly 55% of all batters with lefties providing the other 45% (switch-hitters are factored in to whichever side they hit from) and 71% of pitchers were right-handed by plate appearance thus far this year.  Directly, we can see that a smart manager would love to bat 9 lefties against a righty pitcher as that has a much higher wOBA than running a righty out there to face that same pitcher.  The splits are even wider for left-handed batters as a lefty-lefty matchup has the lowest wOBA and managers seem to show how much they loathe that situation as only about 8% of all plate appearances feature this showdown.  So despite there being more righties than lefties, a manager is just as likely to put a lefty down on his lineup card if he sees James Shields or Wade Davis as the projected starter.  Again, the concept is pretty intuitive, but here you can see how managers have faced this scenario and the results that have occurred.  Let’s take a look at how each team approaches each scenario:

There’s quite a bit going on here so allow me to frame the discussion before looking at the results.  For instance, the Rays, it’s probably more correct to say Joey Madds made the decision, have ran a righty out to face another righty 28% of the time which is well below the league average of 35% (green cells for teams that are properly splitting, red for teams that aren’t), while getting a lefty batter on righty pitcher 41% of all plate appearances.  This is really good since we discovered above that that is the ideal situation.  You can see that the Rays are pretty close to league-average when facing lefties with 22% of all plate appearances featuring a righty batter (the platoon advantage) and 9% having the dreadful lefty on lefty matchup that is the least preferred of all the states.  We can total up when they have the advantage (LHB v. RHP + RHB v. LHP = 63%) to see that the Rays have the second highest likelihood of being in a favorable situation.  The Yankees are the only team ahead backed by their absurd 46% of all plate appearances featuring the ideal state of LHB v. RHP.  You can probably come back to the wRAA column as it will be further explained later in this post.  Go through this as you will to find peculiarities or things that stand out (my list would probably start with the Rangers having just 27% of their plate appearances in the ideal state which could point to them lacking a lefty bat or the fact that the Twins have a full 15% of all their plate appearances in the absolute worst scenario), but I would like to move on to attempting to evaluate this and try to find why teams like the Blue Jays take half of all their plate appearances in a less than ideal scenario (short answer probably involves something about Cito Gaston thinking he’s still retired).

(Click the chart to open a larger image in another tab)

The idea here is to come up with wRAA for each scenario so that we can use wOBA and plate appearances to see how much offense has been contributed in each scenario.  The wOBA uses the formula from The Book and does not include any base running measures, only what they did at the plate.  You would read this as the Rays have a .315 wOBA when they have a right-handed batter against a right-handed pitcher.  We can use the first chart to see that the average of all AL clubs in this scenario is .324.  It makes sense for the Rays to try to avoid this situation as much as they do because they fail more than the average offense in this situation.  A team like the Blue Jays, however, have a wOBA of .350 in that same matchup and may explain why Cito has no problem facing that matchup nearly every other plate appearance.  This is where wRAA comes in.  We can use this formula:

(wOBA-Lg. Avg. wOBA)/1.15*PA

where Lg. Avg. wOBA is for each scenario.  The Rays offense has cost almost 13 runs when a righty faces a righty, BUT, that number would be even higher if Joe Maddon didn’t funnel out of that situation as often as he does.  There are only two teams (Yanks & Twins) that have less total plate appearances in this situation and for good reason as we have shown that there is a better roster alternative, barring you have some roster flexibility.  Meanwhile, the Rays have the 3rd MOST plate appearances of a lefty batter facing a righty pitcher where they hit about 36 points of wOBA better, and about 8 points better than league average for that scenario.  So in this instance, the Rays have contributed almost 18 more runs than the average offense going by (.351-.343)/1.15*2,430.  Other teams might have a higher wOBA in each situation, but it’s probably because they have better overall talent.  The point of this exercise is to see which teams are leveraging their strengths and minimizing their weaknesses.  As an aside, I hear all this talk for Gardy or Tito or even Girardi (huh?) for Manager of the Year.  It just utterly blows my mind that Joe Maddon is not a front runner in this farce of an award.  How do people think we win, by magic?  Our offense is fairly pedestrian and yet we’re going to win close to 100 wins.  Get your stuff together and put any manager up against Maddon and I’d love to be a part of that debate.

Looking at the numbers versus lefties we see that the Rays have a .349 wOBA (.334 league average wOBA) which they wield about 22% of the time and contributes another almost 18 runs above the average offense, because yet again they have the 3rd most plate appearances in this preferred alternative.  In the worst scenario, the Rays are slightly above average at 9% of all their plate appearances in this scenario, where they are hitting a not great .314, BUT, that’s still almost 10 points better than a league average offense.  So they still seem to be picking their battles wisely in that scenario, or at least better than Trey Hillman’s corpse.  What all this comes down to is that the Rays use their positional/lineup flexibility to create situations that are favorable for them, and they appear to do a better job of this than just about every team in the league.  If we add up the wRAA from each situation we can see that the Rays have accrued 26.5 wRAA, which is middle of the pack, but on the positive-side and almost completely due to them throwing a lefty at a righty instead of ignoring platoon advantages and keeping a righty in when it doesn’t make as much sense.

Check out other teams that may interest you since this is a look at something that I haven’t seen anywhere else, but if you’re a Mariners fan you might want to cover your eyes, or perhaps plugging your nose would be better advice.


About Jason Hanselman

Rays fan.
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