I like Avery as much as the next guy....but for a starting NBA guard:
a) He is a very good on-ball defender, probably top 10%.
b) He is limited offensively: He is not a natural point, if one at all, has limited range for a 2. He is a little below average offensively.
Bottom-line is I don't think he is that hard to replace. Yes, we played great when he was inserted in the starting line-up last year - but how much of that was Bradley? It was that same line-up, sans Bradley, that took the Heat to 7....In addition, we now have a solid 4 guard rotation of Rondo, Terry, Lee, Barbosa, with Pierce being able to slot in at the 2 in a pinch.
Meanwhile, we are small at the 4/5, with no real post presence, and are vulnerable to muscular, aggressive 4/5 players (Chris Singleton's season high in points came against us, and Reggie Evans looked a few cuts above the journey-man he is...). KG and Wilcox are small for 5s, as are Bass and Sully for 4s.
So, if we can get a skilled big man, who will give us some combination of interior defensive presence, post game, rebounding, and shot-blocking, then I'd be for moving Bradley.