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2014 Marlins Key Questions: Garrett Jones and platoon splits

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Mike Redmond and the Miami Marlins are prepared to try Garrett Jones versus left-handed pitching. How much of a mistake is this?


According to Joe Frisaro of, the Miami Marlins have nine important questions to answer in the upcoming 2014 season, and here at Fish Stripes, we have been tackling all of them. Today's question among those nine: how will new addition Garrett Jones handle left-handed pitching?

4. Is Garrett Jones ready to face lefties? During his years with the Pirates, the left-handed-hitting first baseman belted more than 20 home runs three times. Even in a platoon situation last year, the 32-year-old connected on 15 homers. The Pirates rarely used Jones against lefties in '13. The Marlins, at least for now, say they are willing to let Jones play every day, regardless of who is on the mound. So at least early on, Jones will get a chance to show what he can do against lefties on a regular basis. If he struggles, then a platoon situation becomes inevitable.

Manager Mike Redmond appears ready to at least attempt Jones against left-handed pitching at the start of the season. Unfortunately, every bit of historical information indicates that this is a mistake and that Jones should not be allowed to face lefties. But how much would that cost the Fish?

To answer this, we must first show just how bad Jones has been for his career versus left-handers.

Jones, Career PA AVG OBP SLG wOBA
vs. LHP 526 .193 .234 .344 .252
vs. RHP 2003 .271 .337 .489 .355

That is a difference of 100 points of wOBA, or roughly the difference between Chase Utley (.284/.348/.475) and Darwin Barney (.208/.266/.303) in 2013. That difference is very significant and shows an extreme platoon split. The Book: Playing the Percentages in Baseball says that true-talent platoon splits for left-handed hitters are a 50-50 split between a player's career average and the league average at 1000 plate appearances, meaning that Jones's true-talent platoon split is probably a third as bad as this compared to the league average of 8.6 percent worse versus lefties. Jones's career mark is 31 percent worse.

But that still means that we have some regressing to do to find Jones's true platoon splits. A rough estimate using the methodology listed in this FanGraphs article shows that Jones would still be very bad against lefties, but certainly not as bad as his numbers initially advertise. An estimate for Jones's splits yields a performance 16.3 percent worse versus lefties than righties. Given an estimated overall wOBA of around .313, we have a .324 wOBA versus righties and a .273 wOBA versus lefties for the 2014 season. That is roughly the difference between J.J. Hardy (.263/.303/.433) and Juan Lagares (.242/.281/.352) last season. That still is not encouraging, but it is better than his career marks.

How much worse would that be if the Marlins did not play their lineup ideally? There is a very good chance that Casey McGehee would take the majority of the plate appearances against lefties away from Jones by the early part of the season, but McGehee is already likely to be playing full-time for the Fish. While he may be the platoon partner at first, the player replacing Jones in the lineup essentially is Donovan Solano, who would likely take most of the third base reps in McGehee's place when he plays first base.

Solano is projected to hit a .307 wOBA versus left-handed pitching this season based on a .297 wOBA projection overall. If Jones played full-time over 600 plate appearances versus both lefties and righties, how much worse would that be than if the team tried a true platoon with Jones? From 2011 to 2013, Jones recorded just 176 plate appearances versus lefties in 1433 total attempts, yielding a 12.3 percent rate in lefty attempts. In comparison, a relative full-time player like Logan Morrison saw lefties in 27.5 percent of appearances. In 600 plate appearances, the difference between those two percentages in 91 plate appearances versus lefties. In 91 attempts, the difference in runs between a .307 wOBA and a .273 mark is 2.4 runs.

In other words, the difference in this case is miniscule. Essentially, the Marlins do not have a great option to platoon with Jones like the Pittsburgh Pirates did with Gaby Sanchez (career .388 wOBA versus lefties), so the difference with the Marlins' platoon situation is fairly small. Miami could make the "mistake" of sending Jones up against lefties full-time, but they would lose about a fifth of a win in the process, which in the end is not worth fretting much about.