Realized Platoon Rates

A couple of months ago, I wrote an article about platoon options, and astute reader Tacocat pointed out that platoon hitters never actually realize their versus left-handed pitcher or versus right-handed pitcher splits that we frequently cite. Instead, platoon hitters start games with a platoon advantage, and then sometimes managers have to leave them in to face same-handed pitchers out of the bullpen.

Daily players use the same decision-making as actual managers. You can choose to start a platoon player because he is facing an opposite-handed starter, but that creates a chance that he could see a plate appearance versus a same-handed reliever later in the game. If you are relying on a split stat versus left-handed or right-handed pitchers to make that start/sit decision, then your platoon hitters will underperform your expectations on average.

Fortunately, we can do better. I started by trying to answer the simple question of how often hitters who start games with the platoon advantage actually see the platoon advantage in all of their plate appearances in those starts. With play-by-play data, that is pretty easy to answer. Since 2002, left-handed hitters have seen the platoon advantage in 82.9 percent of the plate appearances in starts in which the opposing starter was right-handed. Right-handed hitters have seen the platoon advantage in 50.7 percent of their plate appearances in starts in which the opposing starter was left-handed.

Those percentages provide a potential weighting to apply to hitter versus left-handed and versus right-handed splits, but I think they oversimplify the nature of platooning. Many hitters are good enough that they play pretty much every day, and obviously those hitters will sometimes start games in which the opposing starting pitcher provides them a platoon advantage. We shouldn’t expect those hitters to be removed in late-inning situations when same-handed relievers enter the game, so I suspected those percentages somewhat understated how often true platoon players faced opposite-handed pitchers in their platoon starts.

To solve that problem, I needed to answer a separate question of what constitutes a platoon hitter. To do so, I looked at the percentage of all starts hitters saw versus opposite-handed starting pitchers and attempted to find the logical boundaries between everyday players and platoon players. Here are the left-handed hitters from 2015 sorted from the highest to the lowest percentage of starts with the platoon advantage over the opposing starting pitcher to illustrate.

LHBs w/ Highest Pct. of GS w/ Platoon Adv., Min. 40 GS, 2015
Hitter GS Platoon Adv vs Starter
Chris Coghlan 119 100.0%
Kelly Johnson 78 100.0%
Andre Ethier 106 99.1%
David Murphy 92 98.9%
Grady Sizemore 66 98.5%
Ike Davis 61 98.4%
Tyler Collins 50 98.0%
Michael Conforto 48 97.9%
John Jaso 48 97.9%
Scooter Gennett 93 97.8%
Skip Schumaker 41 97.6%
David DeJesus 75 97.3%
Seth Smith 107 97.2%
Conor Gillaspie 69 97.1%
Pedro Alvarez 124 96.8%
Alexi Amarista 87 96.6%
Will Venable 81 96.3%
Jake Lamb 89 95.5%
Dustin Ackley 67 95.5%
Ezequiel Carrera 44 95.5%
Ben Paulsen 79 94.9%
Matt Joyce 74 94.6%
Alex Avila 56 94.6%
Miguel Montero 91 94.5%
Clint Robinson 77 93.5%
Carl Crawford 43 93.0%
Matt Adams 42 92.9%
Alejandro De Aza 81 92.6%
Ryan Howard 118 91.5%
Justin Bour 102 91.2%
Travis Snider 65 90.8%
David Peralta 116 90.5%
Derek Dietrich 71 90.1%
A.J. Pierzynski 105 89.5%
Domonic Brown 47 89.4%
Cody Asche 112 89.3%
Eric Sogard 102 89.2%
Kyle Schwarber 59 88.1%
Adam LaRoche 116 87.9%
Stephen Drew 105 87.6%
Ryan Goins 112 87.5%
Adam Lind 135 87.4%
Anthony Gose 125 87.2%
Yonder Alonso 94 87.2%
Jon Jay 53 86.8%
Sam Fuld 75 86.7%
Curtis Granderson 144 86.1%
Gregory Polanco 137 86.1%
Stephen Vogt 115 86.1%
Lonnie Chisenhall 86 86.0%

It isn’t completely cut and dried, but I see the transition for left-handed hitters happening around 89 percent. Just above that threshold are players like Alejandro De Aza, Ryan Howard, and Travis Snider who each had platoon partners I could (sort of) easily identify—Shane Victorino and Rusney Castillo, Darin Ruf, and Steve Pearce and Nolan Reimold. Meanwhile, just below the threshold are players like Kyle Schwarber and Adam LaRoche who generally played every day when they were healthy and on their rosters.

RHBs w/ Highest Pct. of GS w/ Platoon Adv., Min. 40 GS, 2015
Hitter GS Platoon Adv vs Starter
Ryan Raburn 50 100.0%
Franklin Gutierrez 42 78.6%
Shane Victorino 50 70.0%
Jake Smolinski 50 68.0%
Brandon Guyer 79 67.1%
John Ryan Murphy 43 65.1%
Clint Barmes 51 64.7%
Mike Aviles 79 64.6%
Josh Phegley 62 64.5%
A.J. Ellis 55 63.6%
Chris Young 77 61.0%
Tim Beckham 51 60.8%
Scott Van Slyke 53 60.4%
Jonny Gomes 55 58.2%
Nolan Reimold 45 57.8%
Wilin Rosario 54 55.6%
Darin Ruf 62 54.8%
Shane Robinson 48 54.2%
Gordon Beckham 50 54.0%
Jeff Francoeur 71 53.5%
Danny Valencia 85 52.9%
Kiké Hernandez 51 52.9%
Jake Marisnick 101 52.5%
Paulo Orlando 63 52.4%
Chris Carter 112 50.9%
Rajai Davis 73 50.7%
Joey Butler 61 49.2%
Melvin Upton Jr. 47 48.9%
Chris Denorfia 45 48.9%
Hernan Perez 66 48.5%
Steve Pearce 79 46.8%
Alex Guerrero 49 44.9%
George Springer 101 44.6%
Peter Bourjos 41 43.9%
Aaron Hill 73 43.8%
Mike Napoli 115 43.5%
Domingo Santana 44 43.2%
Delino Deshields 110 42.7%
Chris Johnson 61 42.6%
Justin Maxwell 59 42.4%
Mark Canha 108 41.7%
Delmon Young 41 41.5%
Kelby Tomlinson 46 41.3%
Robinson Chirinos 73 41.1%
Mark Trumbo 132 40.9%
Evan Gattis 147 40.8%
Michael Morse 57 40.4%
Elvis Andrus 159 40.3%
Jake Elmore 40 40.0%
Adrian Beltre 143 39.9%

From the right side, I’m seriously impressed the Indians were able to start Ryan Raburn in 50 games without any of them having a right-handed starter. More on point, the right-handed threshold is around 45 percent, below players like Chris Denorfia (platooned with Chris Coghlan and Mike Baxter) and Rajai Davis (platooned with Anthony Gose) and above players like George Springer and Mike Napoli.

Next, I recalculated how often hitters who start games with the platoon advantage actually see the platoon advantage in all of their plate appearances in those starts using only hitters who exceeded those thresholds in 40 or more plate appearances each season. That added filter increased the left-handed platoon advantage to 84.9 percent (up 2.0 percent) and the right-handed platoon advantage to 52.6 percent (up 1.9 percent).

The next step will be to use those platoon percentages to project platoon hitters in their daily matchups, but I’ll leave that for next week because I’m tired and because I want to have a chance to read any feedback you may have for me.

We hoped you liked reading Realized Platoon Rates by Scott Spratt!

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Scott Spratt is a fantasy sports writer for FanGraphs and Pro Football Focus. He is a Sloan Sports Conference Research Paper Competition and FSWA award winner. Feel free to ask him questions on Twitter – @Scott_Spratt

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It would be cool if steamer would provide split projections. Then we could actually apply this article.