Altherr cleared waivers and was outrighted to Triple-A Syracuse on Tuesday, Andersen Pickard of MLBDailyDish.com reports.
Altherr was designated for assignment by the Mets over the weekend and will remain in the organization after going unclaimed on waivers. The 28-year-old has struggled in 49 major-league games this season, going 5-for-61 with 25 strikeouts.