It's really hard to know what a fitter/lighter Bird looks like.. but it does sound like he's struggling to secure a position in the Top 13, cause there are better options.. other than via injury.
He did play fullback in the past, and im trying to remember why I didnt like it, I think it was a lack of pace, but I cant recall if it was a defensive or offiensive issue.. or both.. like Lomax is my fullback if I wanted a bigger body... and he can jump.. the problem is what do we do with Bird.. if he can bend over and play hooker for 20mins a game then we are laughing.. but im not positive he can.