T.O. is highly unlikely to be resuming his NFL career anywhere in 2013, much less with the Pats.
However, it may be significant that Brady is spending off-season practice time throwing to a 6'3", 226 lb guy who made his living as a deep threat. Regardless of T.O.'s cancerous effect on locker rooms and regardless of how much speed/agility he may have lost at age 39 after two seasons out of football, he's still very football-smart with a wealth of experience to share about running deep routes from a receiver's perspective.
I think this may be Brady "studying up."