Walters was designated for assignment by the Mets on Tuesday.
As such, Walters will be removed from the 40-man roster in order to add James Loney, who was recalled to the major league ranks Tuesday. Walters, who's remained at Triple-A Las Vegas this season, will be subject to waivers, but it's unlikely he'll be claimed considering he's allowed 23 earned runs on 38 hits in 22.1 innings on the year.