CHARLOTTE – If you've spent any time around the Carolina Panthers over the last five years or so, you know about the impact Ryan Kalil has made.

But as good as the five-time Pro Bowler has been throughout his 12 years in the league, he plays center, so his contributions quite honestly aren't talked about all that much.

"I don't think people understand what he's meant to this football team," running back Christian McCaffrey said following Carolina's loss to Atlanta in Week 16, the final home game of Kalil's career.

"He truly is the heart of and soul of our team."

McCaffrey hasn't even been with the Panthers for two full years, but it didn't take long for him to understand why the entire locker room follows Kalil's lead.

Jordan Gross can speak on that subject perhaps better than anyone, and he did just that during a lengthy phone interview from his home in Idaho.

The former Panthers left tackle played with Kalil for seven seasons before Gross retired at the end of 2013. They formed an extremely tight friendship through those years in the trenches, to the point where Gross proudly says he views Kalil as a "little brother."

And Gross, like any good big brother, can't heap too much praise without a fair share of ribbing mixed in.

"You don't want Ryan on your team for any sport other than center in the NFL," Gross said with a chuckle. "He's the worst athlete for everything else. Sucks at throwing, no good at darts, bad at pool, bad at basketball, can't bowl. Maybe wrestling because he's so dang strong and squatty.

"He found the one thing that God designed for him to do."

At the top of his profession

When asked to describe the legacy Kalil will leave behind, these were the first words out of Gross' mouth:

"Ryan is the best O-lineman in Panthers history. I would like to say otherwise, but I think he's better than I was," said Gross, who was a three-time Pro Bowler at left tackle, the premium position on the O-line. "He's got a Hall of Fame worthy resume."

Smarts and toughness are the specific attributes Gross pointed to. You've got to have a high Football IQ to succeed at center with all the communicational demands that come with that position on the line of scrimmage.

And as Gross knows, toughness takes on a whole new meaning when you're a starting lineman in the NFL.

"He's had his share of injuries and missed some games, but he's played through more stuff than anybody will ever know," Gross said of Kalil, who has started 144 career games.

What really separates Kalil from other centers though is his ability to get out in space. That's what stood out most to Gross as he reflected back on film sessions in the meeting room – watching Kalil out on the edge and paving the way.

"Ryan pulling on those outside runs, those wide stretch handoffs. He is unbelievable – like no one else I've seen – at getting to the spot he needs to get to before linebackers," Gross said. "He's so explosive and disciplined with his technique and his angles. It's amazing to watch."

That's an opinion shared by many around the league. Left guard Greg Van Roten, who played for the Packers from 2012-13, can speak to that with a tidbit from his time in Green Bay.

"I had never played center before," Van Roten explained. "And my line coach in Green Bay put (Kalil's) film on and said, 'This is how you play center in the NFL.'

"Then to come here last year and be around him and learn from him was just surreal."

Shouldering a heavy load

Before Gross retired, he was a widely respected leader who served as liaison between players and coaches.

When he stepped away, Kalil stepped in.

"He's filled the role that I vacated," Gross said. "He picked up where I left off and took it to another level."

Gross admits it's hard to put into words exactly what goes into being "that guy" in the locker room, that guy everyone looks to for, well, everything.

"I can tell you that being an offensive lineman in the NFL is an incredibly tough job when all you have to worry about is yourself. Then if you choose to take on the role of uplifting teammates and watching extra film with young guys, rah-rah during practice, making sure everybody is on time when they need to be, well that makes your job even more taxing," Gross said.

"Putting out fires – all of that is exhausting."

Head coach Ron Rivera has often made mention of Gross and Kalil's invaluable perspective.

"As much as Coach Rivera would love to say he has a pulse on the team, he doesn't know all the conversations that go on in the locker room, in the huddle or on the sideline," Gross said. "Ryan is somebody that Ron can come to and ask, 'How are guys doing?' That's not easy. A lot of guys wouldn't want to be that guy on the team. But Ryan knows that that's needed."

Kalil also knew more would be required of him when the Panthers selected quarterback Cam Newton with the No. 1 overall pick in 2011.

Newton was transitioning from a spread offense at Auburn and he had a lot to learn, from taking snaps under center more frequently to identifying pressures.

"When we brought Cam in, Ryan's load grew exorbitantly with the protection calls and things like that," Gross said. "He was so good at it that I think the plan was to take that away from him as Cam got more comfortable, but Ryan was just so good at it they kept it on him."

And for that, among other things, Newton has always been grateful.

"Everything goes through Ryan Kalil," Newton said back in 2016. "He's made my life extremely easy.

"He's somewhat of my hidden jewel because he does more things probably for a quarterback than anybody in the league. Sometimes he doesn't get enough credit for it."

Never a doubt?

Gross' favorite Kalil story is one of his first, and it helps explain why Kalil has been so determined to pay it forward in his later years.

When the Panthers selected Kalil out of Southern Cal in the second round of the 2007 draft, his NFL career got off to an admittedly rocky start.

He was given a number he didn't like (65) and he was playing guard, a position he wasn't used to.

"He was so confused as a rookie," Gross said, giggling at the thought of a young Kalil struggling. "Ryan was coming off national championships at USC and the dynamic was so different. I just remember him being so frustrated about how to please the O-line guys. He was playing guard and he'd never played guard. He was on field goal team and he had never been on field goal team."

Then came the home opener against the Houston Texans – Kalil's "welcome to the NFL" moment.

"He was playing right guard and I was playing right tackle and he'd given up a couple sacks to Amobi Okoye," Gross recalled. "Ryan was just so sad and downtrodden late in the game. I remember at a certain point I just started laughing.

"He looked at me and said, 'Why are you laughing at me?!' And I said, 'Ryan, one day you will remember all of this and you'll laugh.' I knew he would pan out."

That's exactly what happened.

After his final home game, Kalil spoke at length about his career winding down. He spoke about the highs and lows. He spoke about all the things he'll miss. He spoke about how fortunate he feels to have played this game for 12 years.

"It's been a great ride," Kalil said.

It sure has.