Let’s talk platoons, more specifically, the right field platoon in St. Petersburg that features two guys named Gabe; Gross and Kapler.
Kapler is the lone right-handed hitter, and the one assured of a steady gig. Throughout his career Kapler has hit lefties well enough for a .828 OPS. Last year the Rays did an excellent job of limiting Gross’ exposure to lefties. In fact, only 21% of his plate appearances came against the same hand. Gross has a career OPS of .786 versus righties and .519 versus lefties.
This tells us that while Gross and Kapler should primarily be used in a strict platoon, there is room for overlap, at least against right-handed pitchers. There are some variables we’re not going to account for here, pitcher splits and leverage of these events come to mind. We can infer that the Rays have basically defeated the idea of using a LOOGY against Gross, because they can simply call upon Kapler to pinch hit.
Let’s assume the duo combine for 700 plate appearances and that Gross sees most of the playing time, about 60%, or nearly 400 plate appearances, and hits for his career average against lefties and righties while seeing 80% righties. Kapler, meanwhile, sees 60% lefties.
When using a league average wOBA of .330, that results in about three offensive runs combined over 700 plate appearances. Take away the 7.5 positional adjustment, add in ~10-15 defensive runs, and 22.5 playing time adjustment and you should get around 28 runs, or about a three win player, only in the form of two players.
As for the Gabe of the Day platoon, it’ll certainly work until the Rays front office deems Matthew Joyce ready for full time action.
Of course, using the last three years instead of career splits will result in more accurate numbers, but this is intended as a rough sketch of what a properly executed platoon can bring to the table. Sometimes, quality and quantity go hand in hand.