CHARLOTTE, N.C. -- Shouts of "Luuuuuke" reverberated through Bank of America Stadium when Carolina Panthers middle linebacker Luke Kuechly was the last player introduced before Thursday's prime-time game against the Philadelphia Eagles

There was stunned silence when Kuechly jogged to the locker room late in the first half to be evaluated for a concussion. He never returned, entering the concussion protocol for the third time in three seasons.

A game in which the Panthers could have made a statement as the best team in the NFC turned into a 28-23 loss amid concern for the health of their defensive leader.

“Health is a big thing," Panthers nickelback Captain Munnerlyn said. “You can’t keep having those things. I just pray for him and hope all is well."

Carolina quarterback Cam Newton did all he could to keep pace with the Eagles, who scored 25 of the game's next 31 points after Kuechly left. Newton had the Panthers (4-2) within a touchdown when he threw an interception with 3:06 remaining in the contest.

But ultimately, this came down to the fact that the Carolina defense didn't have an answer for quarterback Carson Wentz and Philadelphia's offense once Kuechly left.

Instead of Carolina re-establishing itself as a Super Bowl contender, questions resurfaced about the prospect of defensive life without Kuechly.

Again.

“We need Luke," Newton said. “I didn’t know he was out for the most part of the game. But his presence was missed. We kind of had a lethargic wave there in the third quarter."

Kuechly missed three games in 2015 with a concussion suffered in the opener at the Jacksonville Jaguars; he was in the concussion protocol for three games. In 2016, he was held out the final three games as a precaution, after suffering his second concussion in a prime-time game against the New Orleans Saints.

There were no tears when Kuechly left the field this time, as there were when the Pro Bowl player exited on a cart during the game with Saints. But there is concern, because the 26-year-old is the quarterback of what was the league's third-ranked defense coming into the night.

How long he'll be out remains to be seen. Because the Panthers don't play for 10 days, there's a chance Kuechly could be back for the Oct. 22 game at the Chicago Bears.

The good news is the defense will have a chance to prepare for upcoming opponents with David Mayo, who finished Thursday's game at middle linebacker, after getting only mental reps in preparation for the Eagles. Carolina thought enough of Mayo's play at the end of last season that it didn't re-sign veteran A.J. Klein.

But on this night, the defense struggled without Kuechly, the 2013 NFL Defensive Player of the Year.

The Panthers were leading 10-3 when he left the field after his left shoulder and neck collided with an Eagles lineman on a second-and-4 play from the Carolina 6-yard line. The Panthers were still leading by that margin when Kuechly went to the locker room.

Then the Eagles scored on Wentz's 1-yard touchdown pass to Zach Ertz, a play where Kuechly likely would have drawn coverage on the tight end. Ertz scored another touchdown in the third quarter, on a pass over the middle.

When Wentz hit Nelson Agholor for a 24-yard touchdown over the middle, the Eagles went up 28-16.

So the Panthers didn't make the statement they hoped. They also didn't give up.

Newton continued to make plays with his arm and legs to cut the lead to 28-23. He sacrificed his body with a scramble and dive that came up just short of the goal line. He utilized his weapons as he did the previous two games, when he played to his 2015 MVP level.

He also made more mistakes in four quarters than he did during those previous two weeks. He had only one touchdown pass and three interceptions on Thursday, after throwing six touchdowns to one interception in victories at New England and Detroit. He had a passer rating of 48.5 against Philadelphia, after compiling consecutive ratings of 130.8 and 141.8.

"We didn't have good ingredients to win," Newton said. "Turning over the ball as many times as we did, giving them layup scores. In order to win a game like that, you have to protect the football better. I am mostly talking about myself with that.

"We went up 10-3, they got their touchdown on a turnover by us, and that can't happen. We have to be better and understand championship football at its finest."

The Panthers need Newton to play at a higher level if they hope to win should Kuechly be out for an extended period. They still can be a championship contender. They went 3-0 without Kuechly during their magical 2015 run to the Super Bowl.

They still can make a statement this season.

They just couldn't make one Thursday night -- other than that they need Kuechly in big games like this.

“That’s our first dose of playoff-caliber football," Newton said. “And we will be better from it."