Why didn't the yankees resign sergio mitre?

Something's confusing me. He had a fantastic record, a marvelous, just marvelous era, and an absolutely fabulous number of strikeouts and a very low/scarce WHIP, homeruns and RBIs. Although he had a very slightly rough post season last year, he was still a absolutely spectacular pitcher to have in the bullpen. What an awful moment for all us yankee fans, he will be missed greatly. Cashman is an idiot.