I think each team carries 12 players at a time. Right now ND will probably lose Abro, Dragicevich is transfering, and Crowley is a walk-on.
That leaves 9 Scholarship players. With 3 recruits coming in next year to bumped the total back up to 12. After next year ND loses Cooley and Martin (if he is able to get a 6th year which he may)
With the two recruits coming in from 2013 that will bump the total back up to 12. This is all without anyone transferring.
EDIT: Forgot Brooks with graduate after next year, also. From what I have heard Broghammer may be done because he has bad knees, but if he does still play he still has two years left. That leaves either 10-11 players after next season. Room for 1-2 more players to sign in 2013.