"We are repping a lot of the kids that are redshirt guys that were on the scout team, so they get a chance to run some reps running our stuff and that's a good thing," defensive coordinator Jeff Casteel said.
"We try to let some of the older guys heal up a little bit and get some young guys some reps. You get 14 or 15 practices or whatever it is and then we get back in March and get them again."
The practices benefit those younger players because it gives them a closer look at what they will consistently see next season.
"A lot of the younger kids, it is the first time they have heard our terminology and they are still not in some of the meetings, but they are doing a good job getting reps and running around and trying to make some plays," Casteel said.
Arizona's defense was better this season, but it still is not at the point that Casteel would like to see it reach.
"We made some improvement, but we are still working and in progress," he said. "We are a little bit better than what we were last year, but we have to continue to improve. Our effort has to improve and at times we're just not consistent enough.
"We have to become a much more consistent defense. We have to continue to rep them where they are comfortable playing full speed. We still have some depth issues, so some of the older guys may get run down and it makes it tough on them, but we are making some strides."
There is one more challenge for the defense this season, as it will face a Boston College team that has one of the best running backs in the country.
"They are very similar to Stanford in the way that they attack people," Casteel said. "Multiple tight ends, linemen, 230-pound back running the gap scheme stuff. They are very good at attacking both sides of the line of scrimmage and they have a good play action game.
"I think they found their stride the last four, five, six weeks of the season by getting into those big sets and pounding people and putting people in conflict with the play action game. It is going to be a challenge and we have not seen that type of offense this year because we didn't play Stanford.
"I don't know if we've seen anybody like him (Williams). He is a big, strong kid with good speed and he squares his shoulders and puts out punishment on guys, especially when he gets down through the line of scrimmage. If you don't get to him and slow him down, he is a bull coming through there."