Cardinals quarterback Trevor Knight sees an increase in snaps when a veteran signal-caller has a day off.

Linebacker Haason Reddick is running with the first-team defense already, but most rookies at Cardinals training camp are scratching and clawing for snaps.

Undrafted quarterback Trevor Knight is often the odd man out during 11-on-11 work, watching idly as veterans Carson Palmer, Drew Stanton and Blaine Gabbert get in their work.

There is, however, a lifeline that he and the other youngsters can hang on to: coach Bruce Arians has been liberal thus far with days off for his veterans, and that means more work for the rookies.

"On the day where there is only three guys working, (Knight) gets a ton of reps," Arians said. "Obviously, when it's a four-man day, he doesn't get much. Same with when Larry (Fitzgerald) is down. Younger receivers get more. It's a double edge (advantage). You give a guy a break, but you're looking at other guys, too, for a reason."

Knight said he often learns the night before that a veteran ahead of him will be taking a day off. In three of the last four practices he has gotten significant work.

"You can sit in a film room, and be on the board and learn stuff out of the book all day long, but there's no substitute to actually getting out there, running through it and seeing it live," Knight said. "That's been unbelievable for me. I try to take every single rep and make the most of it."

Arians said Knight is still swimming in the mental aspect of the game, which is not unexpected for a rookie signal-caller in an intricate offense, but he has shown slivers of promise.

 "He's progressing," Arians said. "This is a lot on his plate, this offense to learn. Sometimes it's paralysis -- you'll look at blitzes and all of a sudden your arm will go numb and you can't hit a guy wide open. That's a natural thing. It's not a thing where you say, 'Oh, man, he can't throw.' He can throw, it's just, can you throw what you're thinking?"

Arians said Knight does possess two distinct strengths: "Running the hell out of the ball and long passes."

The change in available snaps isn't as pronounced at other positions, but rookie T.J. Logan took advantage of increased work on Thursday during Chris Johnson's rest day. The fifth-round pick said it's a jolt when he hears there will be more playing time available due to a veteran's day off.

"You want more tape on film," Logan said. "And it lets me know that maybe if I get to that point, I'll get the same thing."

JOHN BROWN STRAINS QUADRICEPS

Wide receiver John Brown will be out for a few days to a week with a strained quadriceps, Arians said. Brown was racing for a pass in the end zone on Thursday when he felt the muscle tighten and left practice.

Brown dealt with the sickle cell trait and a cyst on his spine last year, which robbed him of his regular explosiveness, but Arians said the injury is not related to either of those. Arians does not believe Brown will be more susceptible to injuries moving forward.

Wide receiver Aaron Dobson injured his hamstring during practice and will be out longer than Brown, Arians said. Right tackle Jared Veldheer missed practice on Thursday for personal reasons and returned Friday. Safety Ironhead Gallon (knee) returned to practice on a limited basis. Linebacker Jarvis Jones (quad) and defensive tackle Ed Stinson (hamstring) remain day-to-day.

RED & WHITE PRACTICE SET FOR SATURDAY

The Cardinals are holding their annual Red & White Practice on Saturday at University of Phoenix Stadium. It will go from 2-4:30 p.m., and the entire team will sign autographs on the lower field wall along both sidelines after practice for a limited time prior to leaving the field.

Admission and parking are both free. Those who bring three cans of food for St. Mary's Food Bank will be entered into a drawing to win a pair of season tickets for the 2017 season.

Fans can enter the stadium beginning at 1:30 p.m. Arians said there will be more live scrimmaging than in years past.