Leiter underwent arthroscopic surgery to remove a loose body from his right ankle region Tuesday and should be considered out indefinitely, Kennedi Landry of MLB.com reports.
Leiter is expected back before the end of the season but is without an official recovery timeline, so it's safe to assume he'll be sidelined for the foreseeable future. The right-hander landed on the injured list over the weekend due to a posterior impingement in his right ankle, which he apparently has been pitching through for most of the campaign.