From Tyler Kepner:

The Yankees could lose Ron Villone if they do not promote him soon. Villone, who pitched in 70 games for the Yankees last season, has 23 strikeouts in 21 2/3 innings for Class AAA Scranton/Wilkes-Barre, with a 1.66 earned run average. Villone, who earned a save last night, has a clause in his contract that allows him to become a free agent on May 15.

Via PSD.