Rookie linebacker Shaq Riddick in action at training camp on Thursday.

For the vast majority of training camp, fifth-round draft pick Shaq Riddick had more in common with the fans watching the Cardinals in the stands than his teammates on the field.

Each day he came out in a shirt and shorts, unable to participate because of a balky hamstring which was originally injured in offseason workouts – causing him to miss almost every summer practice as well -- and aggravated early at camp.

"You feel like you're on the outside of everything," Riddick said. "It's just not fun. You've got all the vets and all the older guys nagging on you because you aren't playing."

The rookie outside linebacker finally made his return to the field this w

eek and is likely to make his preseason debut on Sunday night against the Raiders. He said he was cautious with the injury in his first full practice on Wednesday but turned it up Thursday.

"He shows what we drafted," coach Bruce Arians said. "A big tall guy who can really run, come off the edge. He's got some good strength at the point of attack, which should be his forte because he was a down lineman. But it looks like he can handle the sight lines of an outside linebacker. A pretty bright guy."

Riddick had six sacks in nine games last season at West Virginia, and was drafted as another edge-rushing possibility opposite Alex Okafor. He feels like he has the skills to contribute, but realizes it will be an uphill battle with the season near.

"This is my second day with a pair of shoulder pads on," Riddick said. "Of course I'm behind. I'm at the bottom of the depth chart."

Despite missing so much time, Riddick seems likely to make the roster. When asked if he can be evaluated in such a short timespan before the cuts, Arians responded: "I don't think you'll know until probably Thanksgiving, like most rookies."

PRACTICE SQUAD  POSSIBILITY FOR THIRD QUARTERBACK

Arians expects the third quarterback competition between Logan Thomas and Phillip Sims to be undecided until final cuts, with t

heir play in the fourth preseason game next week a big factor. No matter which one wins, there's the possibility he goes on the practice squad instead of the 53-man active roster to save a spot for another position.

"It's kind of the norm now in the National Football League to have two and a guy on the practice squad," Arians said. "It wouldn't be out of the question."

That would leave open the possibility of another team taking the practice squad quarterback and placing him on its active roster – like the Cardinals did with Ryan Lindley from the Chargers last season – although Arians doesn't seem too concerned about that.

"If they want to put him on the active roster without knowing anything about him, yeah, they can do that," he said.

POWERS, WEATHERSPOON, CHRIS JOHNSON COULD PLAY SUNDAY

Cornerback Jerraud Powers, linebacker Sean Weatherspoon and running back Chris Johnson tested their hamstrings by running on the side during Thursday's practice. If all goes according to plan, they could return to practice Friday, which would put them in line to "definitely" get some playing time on Sunday night against the Raiders, Arians said. None has played yet this preseason.

Defensive end Ed Stinson injured his toe and wore a walking boot while sitting out practice Thursday. Arians hopes he can play in the final preseason game against the Broncos. Stinson went on injured reserve with a toe injury last season, but this is a different toe.

Tackle Rob Crisp (knee) had a setback after returning to practice Wednesday and sat out. Tight end Troy Niklas (hamstring), wide receiver Michael Floyd (hand), guard Mike Iupati (knee), wide receiver Travis Harvey (hamstring) and safety Ross Weaver (unknown) missed practice. Earl Watford (ankle) returned and saw time at second-string right tackle as he attempts to battle there for playing time.