What to do with Tretter? Just look at the ages of the Packers starters:
Bakhtiari 23
Sitton 28
Linsley 23
Lang 27
Bulaga 25
Of course, Tretter still has to prove he can make it to the regular season healthy. But if he does, they'll have to find a spot for him or lose him to FA in a couple years. I think Lang is the one most vulnerable to a challenge, but MM really likes him.