Raiders working on their offensive line

Posted by ESPN.com's Bill Williamson

The Oakland Raiders have been busy Tuesday, trying to upgrade their offensive line after losing center Jake Grove to Miami.

The team has signed former Denver tackle Erik Pears and is visiting with Buffalo center Melvin Fowler. The Raiders are also reportedly visiting with quarterback Charlie Frye and tackle Ray Willis, who both played for Seattle last season.

Oakland is clearly trying to upgrade its offensive line and create some competition at several positions. Frye could be a potential backup option behind JaMarcus Russell in Oakland.

Meanwhile, free agent guard Cooper Carlisle is talking to several teams including Oakland. A deal could come this week.