CHARLOTTE, N.C. -- Is "Double Trouble" back?
If anybody on the Carolina Panthers' coaching staff knows, it would be running backs coach Jim Skipper.
Everybody else on the Carolina coaching staff has to watch film to appreciate just how potent this one-two punch was for a three-year stretch before Stewart began having injuries that limited him to only 15 games the past two seasons.
So Skipper can speak better than anyone on whether the backs, aptly nicknamed "Double Trouble" five years ago, are back as Carolina prepares for Sunday's opener at Tampa Bay.
"It's all there," he said. "Oh, these guys, they really haven't lost a step. If anything, they've gained overall experience so that's got to enhance their overall game. It's good to see these guys all healthy and back at it."
Carolina coach Ron Rivera has watched film of Williams and Stewart from 2009. He says they, along with fullback/running back Mike Tolbert, can be dynamic.
That would make Williams and Stewart the "Dynamic Duo."
The key, outside of a rebuilt offensive line, is keeping Stewart healthy, something he hasn't been since the 2011 season when he rushed for 761 yards and caught 47 passes for 413 yards due to severe ankle injuries that required surgery on both.
After recovering from a hamstring injury that kept him out of all of training camp in Spartanburg, South Carolina, and forced him to miss the first preseason game, Stewart has looked like his old but new self.
"He looks like he did when he first came in," Skipper said. "That's all a big plus. To his credit, he kept on grinding while trying to get healthy and he stayed into the game mentally.
"The only thing he couldn't do was be out there physically, but mentally he was a pro in the classroom."
Stewart has shown flashes of his ability in the preseason. He scored twice in an Aug. 17 win against Kansas City, the first time he'd been in the end zone since 2012.
"He runs so hard," center Ryan Kalil said. "He doesn't go down. He fights for every yard. With that you get some of the nicks and knacks that he gets. The guy just fights and fights and fights.
"I know it kills him to not be able to stay out there all the time, but it's part of the game. When he does get back out there you realize why he is so special and why you keep giving him chances to come back."
Williams has been quiet during the preseason -- at least as it pertains to interviews. He hasn't done any. He lost his mother to breast cancer in May, and anybody that knows the 31-year-old back knows they were close.
"Outwardly, he's the same," Skipper said. "But you know that is a tough thing for him to go through, and he's probably dedicating the season to his mom, and that's all good."
Williams appears to have found the fountain of youth. He led Carolina in rushing last season with 843 yards to go with 26 catches for 333 yards. At an age when most running backs see a significant drop in production, he looks as strong as ever.
But having Stewart back will help. Not only will it give the offense a change of pace -- Stewart is the more physical inside runner and Williams quicker off the corner -- but it keeps the numbers of carries for Williams down.
Fresh legs typically mean more production, particularly at an older age. But again, the line must perform, particularly against a stout Tampa Bay defensive front.
"Yes, Double Trouble, baby!" Rivera said at the mention of Williams and Stewart. "They can be a formidable group again. If Jonathan can continue to stay healthy and perform the way he did on a consistent basis, we're going to be back to where these guys can be. We'll be very productive, that's for sure, especially as a tandem."
Skipper likes the depth one through four, adding little-known Fozzy Whittaker to the mix. Whittaker was impressive enough during the preseason, leading the team in rushing, to make 2013 sixth-round pick Kenjon Barner expendable in a trade to Philadelphia.
"All can play," Skipper said.
But one and two are the keys.
"That's how things started out when I got here," Stewart said. "I know a lot of people have been missing that. We missed it. I missed it. I'm pretty stoked about it."