Cardinals running back Kerwynn Williams works at a recent OTA.

Kerwynn Williams is a picky eater, one of the reasons he turned to the Kerwich.

As a high school senior, weighing only 155 pounds, Williams needed to add weight. He was a peanut butter and jelly fan, but singular sandwich "was not getting it done." So he turned to the Kerwich – lathering on a couple layers of peanut butter and a couple layers of jelly.

"Slice it in half, dip it in milk, call it a day," the Cardinals running back said.

Whether the Kerwiches helped get Williams up to his current weight of 198 pounds on his 5-foot-8 frame may be debatable. That's less because of the caloric intake and more because Williams simply has worked his way into NFL

relevance.

Barring any roster moves, Williams stands to be the Cardinals' top backup for star starter David Johnson going into this season. For a guy who bounced around so much in his career – since coming to the Cardinals in 2014, Williams has been either signed or released by the team 11 times – nothing is promised.

"I feel like this is truly what the NFL is," Williams said. "Not everyone gets to come in as a first-round draft pick. Not everyone is a highly touted player or free agent. You have to grind and make the best of your opportunities. You're not going to get a thousand of them. Something easily could have gone wrong in any of (my) opportunities. I could have done something wrong at any time. But you can't focus on how many opportunities; you have to make those opportunities count."

Just two years ago, Williams was behind Andre Ellington, Chris Johnson, rookie David Johnson and Stepfan Taylor on the depth chart. Taylor didn't return as a free agent this year, nor did Chris Johnson. Ellington, learning to play wide receiver as well as running back, fell behind Williams on the depth chart last season.

Coach Bruce Arians acknowledged there is "always a possibility" the Cardinals add a veteran running back once the team gets to training camp.

"I don't see a glaring need for one right now," Arians said.

Second-year man Elijhaa Penny is in the mix to make the team, and the Cards drafted T.J. Logan in the fifth round. Ellington has been a starter in his career before injuries derailed him.

Williams, meanwhile, has left an imprint.

"Every time we play Kerwynn, he gets 100 yards," Arians said.

Technically, that isn't true, but Williams certainly has performed. In his first NFL start, in 2014, Williams gained 100 yards on 19 carries against Kansas City, and in two other games where he got significant work, he ran for 75 yards (15 carries) and 67 yards (17 carries.) He only had 27 carries all of 2015, but averaged 5.3 yards a carry. David Johnson's emergence last season helped limit Williams to only 18 carries all year, although he averaged 8.7 yards a tote.

"Every time Ker gets an opportunity he makes the most out of it," former Cardinals safety Tony Jefferson, now with the Ravens and one of Williams' close friends, said in a text message. "It always seems when he gets the ball he gains yards. I mean, he was our only 100-yard rusher on the season in '14. He's got a lot of talent he's just been overlooked because of his size ... Proud of that dude. I hope he becomes even more involved as the years progress."

The numbers tell the Cardinals Williams can produce if needed. The numbers also remind Williams that, even as he might move up the depth chart, nothing is promised.

"Don't ever get comfortable," Williams said. "Don't ever feel like you are safe. Things can change at any time."