Carolina Panthers linebacker Luke Kuechly was placed in the concussion protocol and did not return to Thursday's game against the Philadelphia Eagles.

Kuechly left the game after slamming into the arm of Eagles guard Brandon Brooks and ran to the locker room shortly thereafter. This marks the third concussion in as many years for Kuechly, who missed nine games over the past two seasons as a result.

"The only thing I can tell you is that he's in the protocol," Panthers head coach Ron Rivera said post-game. "I don't know anything other than that."

The 26-year-old has been named to the Pro Bowl in four consecutive seasons, earning Defensive Player of the Year honors in 2013. It would be a significant loss for the Panthers' defense if Keuchly misses any extended time, as he and Thomas Davis have been the team's anchor on that side of the ball over the past five seasons.

Kuechly has emerged as arguably the NFL's most well-rounded linebacker, excelling in coverage and run support, while showing a cerebral ability to diagnose plays at the line of scrimmage that is second to none.

Prior to leaving the game, Kuechly recorded four tackles and a quarterback hit.

David Mayo will likely be inserted into the starting lineup in Kuechly's absence.

The Panthers lost 28-23 to the Eagles.

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