From their facebook page
Rand said Larish had the injury checked out around the All-Star break in mid-July (the breaks run concurrently between Triple-A and the Majors) but nothing at that point suggested surgery. He played through it and obviously suffered -- a .247 average after the break, just .185 in August and a 5-for-36 skid over his final 10 games.
The timetable for a return won't be known until they figure out what's wrong in there, so there's no certainty yet whether this affects any offseason plans. He played an awful lot last offseason between the Arizona Fall League and winter ball, trying to get back up to speed at third base.
Larish, who had been playing with a wrist injury before injuring his hand during the team's series in Columbus, will leave the team today.