CHARLOTTE – The status of linebacker Luke Kuechly remains murky.

It's still too early to know if he'll be back to face the Bears this weekend, but one thing was clear:

"He's in the protocol," head coach Ron Rivera said before adding a somewhat positive update. "He's advancing in it, and we'll just see how he is tomorrow."

Kuechly, who exited last Thursday's loss to the Eagles with what was feared to be his third career concussion, wore a baseball cap and jogged around a bit Tuesday as his teammates returned to practice. As far as when he'll be allowed to rejoin them, even the head coach can't predict that.

"He'll be in the protocol until the doctors tell me otherwise," Rivera said, "and then we'll make decisions based on that."

Other injury updates: The Panthers didn't have to provide an injury report Tuesday, but Rivera was "real pleased" with center 's involvement.

Safety Kurt Coleman ramped up his work on the side, and while there's a chance he could practice Wednesday, it may be more likely he'll be forced to miss his third straight game with a knee sprain.

Running back Fozzy Whittaker, who suffered an ankle injury Thursday, was the only Panther not on the field.

Quarterback swap: There was some confusion Monday night when the Panthers promoted Garrett Gilbert from the practice squad, making him the fourth quarterback on the active roster. That was cleared up Tuesday morning when the team waived Brad Kaaya.

So why the switch?

The Panthers didn't want to lose Gilbert to a team currently scrambling for quarterback help.

"We did what we did because of a couple of injuries around the league," Rivera said. "The concern is that you might lose a guy like Garrett who knows our system.

"He's an young up-and-comer with a strong arm who has been in the system for a year now. We liked Brad and what Brad did. ... We had to protect ourselves with Garrett."

Linebacker insurance: The Panthers also need to protect themselves in case Kuechly doesn't play in Chicago, which explains why they signed linebacker on Tuesday.

"Andrew runs very well for a linebacker," Rivera said. "We put him in there with some of the special team stuff today, and he looked good. We had him take a couple of steps on the defensive show team, and he moved very well."

If Kuechly isn't good to go, he'll be replaced by David Mayo. Gachkar, who split his first six seasons between San Diego and Dallas, could then give Mayo a break from special teams.

"Right now I can help on special teams, and with whatever I can learn on defense I'd love to help there," Gachkar said. "I'm familiar with Coach (Steve) Wilks – he coached in San Diego when I was there – so I'm sure there will be a lot of carryover defensively."