Their starting pitching is going to be fine I think. They have Pedro coming back, which obviously helps a hell of alot. Lowe has started to come around, and Wakefield has been fairly solid although his stats are ugly because he got lit up a couple of times. Yes, Fossum and Burkett are shaky pitchers, but every team, even contenders has weaknesses in their starting rotation. Weaver and Petitte are shaky for the Yankees, everyone beyond Morris and Williams sucks in the Cards rotation, the Astros have Miller and Oswalt and a bunch of crap, etc. The Red Sox rotation is fine once Pedro is back at full strength.
The bullpen is what is the problem. That's why they should move Kim back to the bullpen. However, there is no way in hell they are going to use Kim as a middle reliever. It would make no sense to have a shaky closer and a great middle reliever that has been an elite closer in the past. If Lyon is so solid, he can still be solid as a setup man to Kim, and that would strengthen the whole team.