The Chargers' offensive line is set at three spots: Left tackle, right guard and right tackle. Meanwhile, left guard and center are up for grabs.
Zion Johnson, who started at guard for the past three seasons, will compete for the starting center job alongside Bradley Bozeman and free-agent addition Andre James.
As the team began Phase Two of the Offseason Program, this marked the first time they were able to establish a rotation at left guard and center, which saw Johnson and Bozeman get reps at both spots with the 1s.
"That's the way we're doing it right now," Jim Harbaugh said, per the team's official website.