From seeing everyone write so far I would have to agree Raheem Edwards is the most likely to get a contract with the senior team.
Next best guess would be Skyler Thomas (as IIRC he is a CB) for depth (probably getting loaned back and forth to TFC2).
Otherwise, it doesn't look as though there is much use in the waiver or re-entry drafts.
Will Johnson or Benoit Cheyrou as the cover DM depth for when Bradley is away (feel like Cheyrou would be more open to a bench role).
My personal opinion off of the Free Agent list that is available would be the best for depth with us would be:
Jeff Larenowitcz (as centre-back or DM)
Nat Borchers
and just because I liked them when they played for us:
Chad Barrett
Alan Gordon
** Both would be the 4th option strikers behind Ricketts. Hamilton and Babouli sharing most of the time with TFC2 to get chemistry together ala Jozy and Seba