Also, it's not like the other contenders aren't using rookies. Look at the other top teams in the league:
Cleveland -- J.J. Hickson, 46 games played; Trey Johnson, 2 games played
San Antonio -- George Hill, 52 games played; Anthony Tolliver, 19 games played; Malik Hairston, 8 games played
Orlando -- Courtney Lee, 49 games played
Only the Lakers compare with the Celtics in terms of the top contenders in terms of limitation upon rookie minutes; Sun Yue has appeared in more games (10) than Bill Walker (9), but has played fewer total minutes.
I'm not sure that I believe that Hill, Tolliver, Lee, and Hickson are significantly farther along than Bill Walker. I doubt it will kill our chances to give him 5 minutes per game or so.