Alcantara, 21, is currently on the roster of the Yankees' Dominican Summer League team. He tested positive for metabolites of Stanozolol, a performance-enhancing substance, and his suspension will be effective at the start of the 2015 DSL season.
Alcantara has been in the organization since 2012. He was 1-4 with a 4.21 ERA in 18 relief appearances last year for the DSL Yankees.
Bryan Hoch is a reporter for MLB.com. Follow him on Twitter @bryanhoch and read his MLBlog, Bombers Beat. This story was not subject to the approval of Major League Baseball or its clubs.