Luhnow & Hinch said "screw your uppercut swing, Gallo, how about a rover then?" They've said it's something they'll use against certain guys like Gallo. PbP reads "popout to 3B".
Its genius. Pull hitters who get pitched high/away and attempt to go the other way with it (to beat the shift) will pop it up to the 4th outfielder just like that. Basically, giving him the bunt as the only option to beat the shift.