I just picked up Jennings myself, not sure just yet if I'm going to play him. I would consider playing him with LT and Thomas.
Fitz could be hurt so you would have to wait on that for Breaston. I would possibly take a chance on Cribbs, even more so if you get return yards.
Play McNabb
http://forums.thehuddle.com/index.php?showtopic=311782