I am worried.
As long as Rondo can pass and get where he wants to, he will make a difference. His ability to call out defensive sets and get guys 'their' shots is still top notch. Rondo has always played his best when up against the wall.
If he is not totally healthy or the Cs can make him extremely uncomfortable, then it shouldn't be much of an issue. But let's not pretend we played perfectly these last two games without him. In both games, we blew ~20 point leads and allowed the Bulls to come all the way back. Rondo may stifle the Cs momentum.