GREEN BAY, Wis. -- JC Tretter has his old job back.

Two years after he lost his job as the Green Bay Packers' starting center because of a preseason knee injury, he was anointed as the team's opening-day starter at the position.

It means Corey Linsley lost the job in the same way he got it.

Linsley, who stepped in as a rookie after Tretter went down in an Aug. 22, 2014, preseason game, remains on the physically unable to perform list because of a hamstring injury that kept him out the entire offseason as well.

"JC Tretter has had an excellent camp," Packers coach Mike McCarthy said Monday. "I think I've answered that question repeatedly and JC, in my view, has earned the starting position at center. Availability is a big part of what you look for in your players.

"It's unfortunate what Corey is going through and continuing to battle to get back out there. But there's been a lot of time that's gone by since he's been out there. I think JC has done an excellent job."

JC Tretter has his job back as the Packers' starting center, two years after losing the role because of an injury. Joe Robbins/Getty Images

Clearly, McCarthy has placed value not only on Tretter's performance but also in the reps he's taken all offseason with the other offensive line starters. Continuity has long been one of McCarthy's goals for his offensive line. In 2014, when Linsley took over, the same five linemen started 17 of the 18 games (including playoffs).

Last year, only left guard Josh Sitton started every game, and he made one of those starts out of position, at left tackle.

Tretter has made four career starts -- all last season. Three of those came at center when Linsley had a late-season ankle injury. The other was at left tackle in the wild-card playoff game at Washington.

The former fourth-round pick from Cornell did not play as a rookie because of an ankle injury he sustained in spring workouts. He then spent the first half of the 2014 season on the temporary injured reserve list. By the time he was activated, McCarthy felt so good about Linsley's performance that he decided not to go back to Tretter.

Tretter admitted earlier this month that he wasn't sure if he was just holding a place until Linsley came back.

"I think everybody comes into camp competitions, whether it's in a true open competition, to me that doesn't really matter because it doesn't change what I'm going to do," Tretter said at the time.