While I am positive Moore was working out while away from Purdue, there is a huge difference btw being "in shape" vs game shape. Either A) he's just not in game shape yet and he and the staff are being extra cautious and/or B) he aggravated something and isnt/didn't feel ready to go.
As other posters have pointed out, Brohm has eluded to Moore not being ready when camp started back up.
