Cleveland Browns restricted free agent fullback Lawrence Vickers has signed an injury-protection waiver, and will participate in the team's "Organized Team Activity" session today, Jim Trotter of Sports Illustrated reports.

Trotter adds that Browns head coach Eric Mangini is "optimistic" that all the Browns unsigned restricted free agents would participate in the voluntary sessions.

Running back Jerome Harrison, who led the team in rushing in 2009, participated in the team's final session last Thursday. With Vickers signing his one-year tender, that leaves safety Abram Elam and linebackers D'Qwell Jackson and Matt Roth as the three who have yet to sign their tender or waivers.