CHARLOTTE - In 2016 Carolina Panthers quarterback Cam Newton was sacked 36 times, tied for 9th most among NFL quarterbacks.

In the offseason, the team let left tackle Mike Remmers walk, and he signed with the Minnesota Vikings in free agency. Remmers had been responsible for seven of Newton's sacks.

To replace him, the Panthers signed the Vikings former left tackle Matt Kalil to a five-year, $55.5 million contract.

High dollar for a high priority -- protecting Newton, the franchise quarterback.

But through three games, Kalil has allowed five sacks, tied for the most among NFL linemen.

The most egregious happened in the team's Week 3 loss to the New Orleans Saints, when the protection called for the line to slide one way, and Kalil slid the other.

Cam Jordan flew in untouched for a free shot at Newton.

"It's just a mental error," Kalil said after the game. "It's got to get fixed."

Jordan was fine with it, telling the media: “I appreciate him messing up his blocking scheme and allowing me to come free for a sack."

Any coach will tell you there's a multitude of reasons for each sack. The protection called. The quarterback holding the ball too long. Nobody open for a coverage sack.

"I think he’s done a pretty decent job," said head coach Ron Rivera. "I think there’s been some things you can pin on him learning and growing in the system. Some things you can pin on us as to what else goes on in the game."

Plus, in Kalil's case, a new team. New schemes, new offense. New quarterback, one that holds the ball a lot longer than his old one, Sam Bradford.

But Rivera knows Kalil's got to get better, and get better soon.

"I think he’s learning those things and getting part of it now," Rivera said. "But pretty soon we’re going to run out of time so the learning curve has to be now."