Carolina Panthers linebacker Luke Kuechly had to spend another day on the sideline.

Kuechly, who suffered a concussion against the Jaguars in Week 1, was inside during the portion of Thursday's practice open to the media. Coach Ron Rivera said Kuechly eventually came out to the field, but he could only watch.

"He's chomping at the bit," Rivera said. "This is tough on him because again, there's a protocol, and you have to follow it. He wants to be out there in the worst kind of way; that's who the young man is.

"When you've got players like that, it's phenomenal, it's a great feeling, but you also have to be careful. Sometimes you have to save them from themselves."

Currently in the NFL's concussion protocol, the two-time Pro Bowler hasn't yet been cleared for non-contact practice. Once that happens, he then has to pass tests from the team and an independent doctor.

It's impossible to predict how quickly a player will advance through the protocol, but as a point of comparison, cornerback Josh Norman last week participated in three non-contact practices until he was cleared.

While Kuechly isn't on the same timeline, there's a chance he could advance through the final two stages in the next three days. But it's more likely he'll have to sit out Sunday against the Texans, missing his first game since high school.

When asked if he'd err on the side of caution if he had any doubt Kuechly was ready, Rivera said:

"Yes, I will, most certainly. It's no different how I would treat any other player. We did that last year with Cam [Newton] and the rib situation and we're going to be smart about this because it's a long season.

"We can't let him get ahead of himself, and he's also got to be upfront about everything and honest because he wants to be on the field so bad. He wants to be with his guys."