Jonathan Cooper gets his first NFL start Sunday against the Chiefs.

His path, Jonathan Cooper acknowledges, has been "unexpected," a starting job headed his way as a rookie derailed by a broken leg.

The Cardinals' 2013 No. 1 draft pick missed his entire first season, and it took until last week – 12 games into his second season and bolstered only by an ankle injury to Paul Fanaika – to get the guard his first significant NFL playing time. Cooper played 40 snaps against Atlanta, and will start Sunday against Kansas City with Fanaika already designated out.

Playing and playing well are two different things, however, and if Cooper learned anything against the Falcons it was that "Sunday isn't going to get it done so I have a lot of work to do." He said he didn't grade out well in the game, and frankly, it

wasn't surprising to see him with rust.

"Coop did OK for his first outing," coach Bruce Arians said. "Went caveman a few times, lost all his technique and just tried to fight. That's understandable. He left some guys hanging in the middle of the pocket once or twice that he learned from, but I thought the game slowed down for him the more he played.

"He showed some twitch and some power, the things we always knew he had. There were some good things to take out of it. It wasn't his best performance, but some good things to take out of it."

Cooper knows he lost technique too often and simply tried to win by beating up his man.

"We call that going rogue," Cooper said. "You lost all your fundamentals and technique and just try to get after the person. There are times that call for it but in the circumstances I did it, it didn't really call for it."

Cooper will play left guard, with Ted Larsen – who has started at left guard all season – moving to the right side. The left is where Cooper was in training camp, when he began the preseason as a starter. But Cooper suffered a turf toe injury, Larsen eventually took his place and Cooper could not get it back.

Cooper admitted he got discouraged in the past, wondering if he was going to be able to get back to the level that made him a No. 1 pick.

"It's hard when you feel you are healthy and you are giving it your all and you're still getting beat," Cooper said. "That's when you start to question yourself as a player. At that point it's like, 'Well, is this the new me? Am I going to have to adjust my game?' But I am blessed that it seems to be falling back into place. I feel physically I am getting there and technically, I just have to make sure I stay on top of my fundamentals."

Arians said Cooper hasn't earned a starting job back yet, not with the 40 plays in Atlanta. Any start now is out of necessity.

Cooper just plans to keep working, and thinks that significant strides can still be made this season regardless of his spot on the depth chart. As for the pressure of being a number one draft pick, Cooper said he is "past that point."

"I'm sure others aren't past that point," Cooper said. "For me, it's just the pressure of being a good NFL player …"

Cooper stops himself and reconsiders.

"Not a good NFL player, a great NFL player," Cooper said. "But like I said, I have a lot of work to do and a long way to go."

ELLINGTON WILL MISS CHIEFS GAME; FITZGERALD A GAME-DAY DECISION

Considering the Cardinals are trying to push for a division title, the injuries are mounting. Running back Andre Ellington (hip) is not unexpectedly out, with Stepfan Taylor getting the start at running back that will be handled by committee.

Fanaika, safety Tyrann Mathieu (thumb surgery) and defensive tackle Ed Stinson (toe) all were also declared out.

Arians called wide receiver Larry Fitzgerald a game-day decision whether Fitz will play. Fitzgerald, listed as questionable, is still bothered by his knee sprain, but he was officially upgraded to a full practice. Linebacker Larry Foote (foot) was upgraded to limited Friday and is also questionable, as is left tackle Jared Veldheer (ankle). All three are key pieces for the Cardinals.

For the Chiefs, everyone is probable except for defensive end Allen Bailey and wide receiver Junior Hemingway, both of whom will sit out after suffering concussions.