If Rondo's return from injury takes the standard 9-12 months, that means he will be available at the earliest in November and at the latest February. As Rubio has shown us in Minnesota, it may be difficult for an athletic, pass-first, below-average shooting point guard to find his game after returning. To hit the ground running next season, I think Bradley will need to have a big impact.
I think he has the opportunity to take his game to the next level this offseason if he focuses on his ball-handling abilities. He is already a better jump/foul shooter, a better and more willing defender, and is equally athletic (before the injury) as Rondo. If he can sharpen his ball-handling skills and dribble moves - he could be the best backcourt player on the Celtics for years to come.
I could envision him becoming a player similar to Mike Conley - maybe better (13.5 PPG/3 RPG/6.5 APG/2 SPG - 44%/38%/82%). I actually think a Conley style point guard (defense, ball handling, shooting) would be a better fit for this team anyways. He wouldn't be expected to control the offense the way Rondo does/did immediately. Instead, his ball-handling responsibilities would include carrying the ball up the floor, initiating a ball movement/screen heavy offense, and the occasional drive and dish/pick and roll. Compile that with his devastating on-ball defense and his spot up shooting and I say "Rondo-who?".
What do you all think? Does he have what it takes to develop into a starting caliber point guard? Or will he always be an undersized two guard with limited ball-handling responsibilities?
Sidenote: I do realize that if Bradley was the starting point guard that he would be unable to consistently apply his Celtics-famous full court ball pressure, but I'd expect that he would still be a standout half-court defender (something Rondo could be, but chooses not to).