I know this sounds preposterous and I swear I'm not doing this for shock value, but could Rondo's injury actually help the Celtics?
Here's my thinking:
The Heat defense has been successful against the Celtics largely because it sags off Rondo and overplays the Big Three. However, if the Heat perceive that Rondo might be turnover prone, they might actually try to guard him, which would really open up the floor for everyone.
Now this is all assuming that Rondo's arm is in reasonable shape, able to help catch a ball and support the ball on a right-handed shot.
Furthermore, if they choose not to try to pressure Rondo, then Rondo has little to worry about playing with one hand. It's no problem to bobble a ball thrown to you if no one is standing within 10 feet of you.
Again, I'm not going to make some "bold statement" that this is going to definitely happen; however, because of the unique ways defenses approach Rondo, the Celtics might actually be able to benefit from this injury if the Heat decide to actually guard Rondo.