<P> "We're very pleased to have Frank back in the fold on the offensive line and add Mike to our defensive line," said Head Coach Bill Callahan.
"Frank stepped in and played admirably last year and we look forward to having both of these players contribute in the upcoming season."
Middleton had 12 starts for the Raiders at guard in 2001. He originally joined the Raiders in 2001 as a free agent.
"I'm very happy to return now with Coach Callahan as the team's head coach," said Middleton.
Mohring, played in six games for the San Diego Chargers in last season.