SIx-time Pro Bowl offensive tackle Joe Staley is expected to retire from the San Francisco 49ers due to health concerns, league sources told ESPN's Adam Schefter on Saturday.

The 35-year-old Staley, whose contract runs through the 2021 season, wanted to inform the 49ers in a timely way to help find a replacement, sources told ESPN.

The 49ers on Saturday agreed to a trade to acquire perennial Pro Bowl offensive tackle Trent Williams from the Washington Redskins in exchange for a fifth-round pick in this year's NFL draft and a third-round pick in 2021.

Staley, an NFL All-Decade selection, suffered a broken left fibula in Week 2 last season. When he returned in Week 10, Staley suffered a broken and dislocated finger, which cost him three more games before returning in Week 14.

He has played 13 NFL seasons, all with the 49ers, and has started all 181 games in which he has appeared over his career..