From the New York Times:

The Yankees signed the veteran starter Runelvys Hernández and put him in the rotation at Class AAA Scranton. In seven starts this season for Boston’s Class AAA team, Hernández was 0-3 with a 3.06 earned run average. He was 25-33 as a starter for the Kansas City Royals from 2002 to 2006.

Via Eric Schultz.