The Giants transferred Schmitt (knee) to the 60-day injured list Saturday.
The move opens up a spot on the 26-man roster for Yunior Marte, who will start in the second game of Saturday's doubleheader against the Diamondbacks. Schmitt underwent surgery in late July to repair a torn meniscus in his left knee. He's technically eligible to return in the last days of the regular season, but he'll likely be sidelined for the rest of the year given that the Giants are unlikely to qualify for the postseason.