Rookie Corey Linsley looks to replace Tretter in the Packers' starting lineup.
Offensive lineman T.J. Lang reportedly returned to practice, while fellow offensive lineman Jordan McCray didn't take part.
Cornerback Casey Hayward and offensive lineman T.J. Lang exited practice on Tuesday.
No decision has yet to be made on Lyerla's future with the Packers for the 2014 season.
Rookie wide receiver Davante Adams returned to practice on Wednesday.
Wide receiver Jordy Nelson and defensive lineman Josh Boyd returned to action on Tuesday.
Wide receivers Jordy Nelson and Davante Adams along with defensive lineman Josh Boyd all dropped out of practice on Monday.
Linebacker Joe Thomas and running back Rajion Neal are the newest names to the injury list.
Wide receiver Jared Abbrederis and center Corey Linsley missed practice on Friday.
The Packers received more good news on the injury front today....