If I recall correctly he had a couple of decent seasons in St. Louis playing on the outside, when Amendola was on the inside as the slot receiver - about 50 receptions, 700 or so yards - i.e., about the numbers Brandon LaFell had with Carolina. Then he had a knee injury and was moved inside to the slot when he signed with Miami.
Maybe the Pats are thinking he's fully recovered now, and would put him outside again?
Or perhaps they're thinking leave him in the slot and he can take Amendola's place for a lot less money?