UPDATE: Two hours after this article was published, the Twins optioned Matt Wallner to Triple-A St. Paul. I've changed the title to reflect the news.
Trevor Larnach and Austin Martin began the season in a fairly standard platoon, with Larnach facing right-handers and Martin facing left-handers. Martin got an unexpectedly larger share of the early left field reps because the Twins matched up against so many lefty starting pitchers, but the southpaw parade has ended.
It's worked very well, for both players and the lineup as a whole. Larnach has hit .268/.398/.381 for a 119 OPS+ that's 20 points above last year's mark, in part due to being shielded from lefties, against whom he has just one hit all season. Martin has hit .327/.448/.416 for a 143 OPS+, building on last year's second-half success.
As a duo, Larnach and Martin have combined to hit .298/.424/.399 over 243 plate appearances. And the Twins' left fielders — with Larnach or Martin starting 41 of 43 games — collectively rank No. 3 in on-base percentage and No. 4 in OPS out of 30 teams. This is precisely why managers have valued platooning for decades.
Meanwhile in right field, Matt Wallner began the year in an everyday gig, starting against both righties and lefties. It hasn't worked. Wallner has struggled every bit as much as the Larnach/Martin platoon has thrived, hitting .167/.259/.292 with a 39 percent strikeout rate. He went 0-for-4 with four strikeouts Wednesday.
And of late, with Martin thriving and Wallner struggling, manager Derek Shelton has formed a sort of reverse platoon in right field. In the Twins' last dozen games against righties, Wallner and Martin started together in the outfield three times. In five of the other nine games, the righty Martin started over the lefty Wallner.