To get back on topic, Melky Cabrera has struggled this season, to say the least. His performance last year was likely due to seeing better pitches to hit because of guys like Damon, Posada and Matsui hitting around him in the lineup.
Sexson's signing was puzzling to me, but they wanted to see if he had anything left. They took a chance on him and it didn't work out. He had always hit well against the Yankees and they wanted to see if he could hit against anyone else. It was similar to the Twins signing Craig Monroe. Both players, Monroe and Sexson, are likely done. Cabrera could come back. He still has a bit of potential.