Last year, we kept 5 RBs: Sproles, PT, MI, K Rob and Cadet. And if you dont remember what happened to us at RB in 2010, let me assure you, we wont go with only 3 RBs this year...or ever again!
Cadet knows the system and can play RB. But he can also play STs, and thats his bigger value. IMO, he stays.