cartwright actually has a crazy percentage in 3rd and 1 and 4th and 1 situations. its more because he's small and got some leverage than because he's running people over though. duckett could choose to withhold services (no training camp etc) if he didn't get a new deal (and he'd probably like more guaranteed money), but he might not.
I just don't think its a huge need. sellers or nemo should eb able to do it, but we haven't seen them attempt it much (sellers got one carry and on 4th and 1 he got 1 yard and a TD out of it). a 6th or 7th could always be used to sign a new punter
