It might seem like Doc haphazardly uses guys like Leon Powe, Glen Davis and Brian Scalabrine. But there is a pattern here.
He rides the hot guy.
It usually takes an injury to make it happen. That's how we got to know Leon Powe in the first place. It's how Ryan Gomes got off the bench a few years ago. And it's how Brian Scalabrine went from "last man off the bench" to "starter/6th man".
The C's bench was pretty bad during that late December/early January swoon. But Scal actually helped shore things up with some pretty solid play. Eventually, the rest of the bench, including Glen Davis, came around and we started blowing teams out again. Now that Scal is out with a concussion, it's time for the next guy to step up again.
Doc's got no choice but to turn to Leon Powe. We all know what Leon is capable of. But his recent struggles, combined with Scal and Baby's decent play, meant Doc could ride that wave and leave Leon at the end of the bench. He wasn't going to stay there permanently. He was just going to stay there until either Baby or Scal cooled off… or until one of them got hurt.
So expect a lot more time for Leon. And if he gets hot, then maybe Scal will go back to "last man" duties.