J.C. Tretter

Here’s a surprise development for you — J.C. Tretter, who was going to be the Green Bay Packers starting center, has a significant knee injury and will be out multiple weeks.

So said coach Mike McCarthy today. Tretter injured his knee on Friday against the Raiders, but no one noticed because he kept playing. After Tretter and the first-team offense were pulled, his knee started bothering him.

Tretter will now undergo tests to determine the severity of the injury, but no one sounds terribly optimistic.

As you surely know, Tretter missed the majority of his rookie season with a broken ankle, which he suffered during OTAs.

So now what?

That’s something we’ve been asking a lot lately.

Rookie Corey Linsley is now what.

Linsley is taking the reps at center with the No. 1 offense. He was a fifth-round pick back in May.

We all assumed Linsley would come into camp and compete with Tretter for the center job, but the Packers more or less just handed it to Tretter. Now the rookie is being forced to get comfortable with the offense in a hurry.

Linsley has played well enough in the preseason games, but he hasn’t faced No. 1 competition.

This should be interesting.