"These things don't just happen overnight. We're very young at that position."

The news on Burks was "better than anticipated," but neither McCarthy nor Burks specified a timetable on the injury. Burks feels he could return quickly.

"That's what it's looking like" he said. "They'll get me back when I'm feeling good and confident."

Burks said he felt his shoulder pop out during a blocking drill Friday night and wasn't really sure what he was dealing with, but the evaluation from the MRI was positive.

After Martinez and Burks, the next two inside linebackers based on playing time thus far in preseason have been Ahmad Thomas and Greer Martini.

Both have had strong moments in camp and they're playing on a number of special-teams units as well, but they have not played in regular-season games in their brief careers.

"This will be a big game for them coming up in Kansas City," McCarthy said of Thursday's preseason finale. "Not only on special teams, but they'll be getting a lot of reps on defense."

The Packers traded second-year cornerback Lenzy Pipkins to acquire Morrison, a sign the team feels good about its depth at corner. Quinten Rollins, Josh Hawkins, Demetri Goodson, Donatello Brown and Herb Waters continue to fight for roster spots behind veterans Tramon Williams and Davon House, plus top rookie draft picks Jaire Alexander and Josh Jackson.

Jackson has been the star of the preseason, with a pick-six and a second one called back on a teammate's penalty. Alexander snagged his first interception Friday in Oakland.

"They're getting more and more comfortable with what we're asking them to do," McCarthy said. "Their ability to make plays on the ball is something that stood out in the draft process, and they're delivering. The big plays those guys have made, especially Josh two weeks in a row, we're excited about the way they've come on."

As for the young quarterbacks, the battle for the No. 2 job between Brett Hundley and DeShone Kizer will go all the way down to the wire with the upcoming Kansas City game.

Hundley started the Oakland contest with a series of "exceptional" throws, McCarthy said, but offensively things went downhill from there with protection issues and penalties.

"It was a tough night for both quarterbacks," McCarthy said. "From a protection standpoint, it was as poor a performance as we've had, and with the penalties, we had seven or eight plays where we were longer than 19 yards for a conversion."

Backup offensive tackle Kyle Murphy is injured and was dealing with it during a particularly rough game for him, McCarthy said, without going into specifics. Another backup, Jason Spriggs, improved over his earlier preseason games.