Why didn't the Yankees resign Austin Kearns?

Somthing's confusing me. He had an outstanding batting average, a great number of hits, walks and a marvelous number of home runs. Although he struck out a couple times, he was one who could smash the ball all over the park. The yankees made a great move trading for him last year, why not bring him back. Our current DH is 40 and is batting below 200.