I dont think its terrible folks. Hes got a lot of mileage on him, and will be 30 by the time the season starts. Hes carried the ball almost 2000 times in his career. Those kind of number start to haunt RB's.
Truth is Im a bit surprised by this move form the Pats standpoint. Sure hes a big name RB, but Dillon does not seem like a Bellicheck guy at all, especially at this stage in his career. He averaged less than 4 yards a carry while "spelling" Rudi Johnson last season.