The Yankees announced the moves on Tuesday before they played the Minnesota Twins. Aardsma has not pitched since 2010 with Seattle. He had Tommy John surgery last year. Manager Joe Girardi says he will be cautious with how he uses Aardsma out of the bullpen with the Yankees in a tight division race.
Gardner has been on the 60-day DL since April 17 after having surgery on his right elbow. Girardi says it will be difficult to find many at-bats for Gardner down the stretch, but he can use the speedy outfielder as a pinch runner and defensive replacement.