Not sure why it would be hard to understand. Yates knows the playbook, can help teach it to Peterman, if Tyrod gets hurt you plug him in for a few plays or a game or two until healthy. Peterman is not ready to play until he proves otherwise. You don't go into the season with a rookie backup unless he proves he's ready in the preseason. We didn't have the preseason yet and so Yates is our backup. If all goes well, Yates will be among the final cuts and nobody will sign him so he will be sitting at home if for some reason we need to bring him back. Hopefully we don't need him and in the meantime he's just a measuring stick to see if Peterman is any good