FAYETTEVILLE, Ark. - There were more new parts at Justin Wilcox's disposal.

While outwardly that might indicate fewer and simpler schemes for the Tennessee defensive coordinator, it's led to more for the Volunteers defensively. In the system's second season, the players know it better, and Wilcox has a better grasp on his personnel and how to play to their strengths.

Wilcox, who turns 35 today, conceded he'll likely never be able to have his defense do every single blitz, coverage or alignment that he conjures up, but he's been able to do more with this year's defense.

"That's fair to say," he said this week. "As coaches, you really never have in as much as you want because you could sit up there and we do it all day every day. The players we get for an hour of meetings and then whatever, two and a half hours of practice.

"You've got to be careful about adding too much. You don't want them thinking, you want them playing fast, and that's always a fine line you ride. You want to have enough wrinkles that you make it hard for the offenses, but you don't want to slow your players down. That's the gray area."

There's little gray area, though, in how creative Bobby Petrino is offensively, and the fourth-year Arkansas coach will give Wilcox and the improving Vols defense their toughest test of the season. The eighth-ranked Razorbacks have the Southeastern Conference's top offense in points, yards and passing yards on the strength of quarterback Tyler Wilson's arm and Joe Adams and Jairus Wright, a pair of senior receivers who both are near the school's career receptions record.

Wilcox said Petrino has one of the "best offensive minds out there" and praised the Razorbacks' schemes and fundamentals.

"They know how to attack," Wilcox said. "You can tell certain coverages, the quarterback is very sure of where he's going. Every offense has certain route concepts that they like, and some offenses, when you get a certain formation, you know you're getting these concepts. One of the good things [Petrino] does, I think, is he'll run a concept, but he's going to give it to you out of eight different formations.

"It's not like you can line up and know which one's coming, where some offenses you have a good idea based on formations what concepts you're getting."

UT finished 69th nationally last season in total defense with five seniors in its front seven and the talented Janzen Jackson at safety. The Vols are currently 31st in total defense and 28th in scoring defense with a unit that's relied on two freshman linebackers, a trio of junior college transfers and a patchwork secondary.

"Old and young, it's really about the players,'" Wilcox said. "It's about how they prepare, how they practice. They can be freshmen in Psych 101, but they're just a football player out here. It's not always fair to just treat them like everybody else, but that's the way it is.

"We're not going to sit there and say, 'Well, he's a freshman, he made a mistake so it's OK.' It's not OK. The expectation is doing it this way, and I don't care how old you are."

What's given UT's defense problems is stopping both dimensions of opposing offenses. Gearing up to stop Georgia and Alabama's power-run games, the Vols allowed 227 and 294 yards through the air, respectively. UT held South Carolina to 87 yards passing and star receiver Alshon Jeffery to 17 yards, but the Gamecocks ran for 231.

The statistics and players, though, indicate improvement. Most players said the defensive playbook has grown this season, though the game plan depends on the offense. For example, UT kept it simple last week against Middle Tennessee State's up-tempo spread, but tonight's plan is more complex.

"I think they're just putting guys in positions that they feel like can do the best and that can win for the defense," senior defensive lineman Malik Jackson said. "I feel like last year they simplified it for us because it was Coach Wilcox's first year and he didn't really want to overwhelm guys. This year he's kind of opening the book a lot more, putting a lot more plays in and entrusting us with the skill and mindset that we're going to go out there and have a nice game."

Not only is the defense's playbook bigger, but with more players who are better in certain packages against certain offenses, Wilcox has more flexibility to play with during games.

"It's give and take on what we think we're going to need to do," he said. "During the game, there's probably going to be things that we have to see how we handle certain things: how are we handling the run game, how are we handling, are we getting four-man pressure, do we need to blitz more.

"You have to have enough bullets in your gun going into the game, and once you get in the game, all right, here's where this is going, then you take it from there. You need to have an answer. That's the key. If you get into the game and for whatever reason you're struggling with certain things, you have an answer for them."

Said senior linebacker Austin Johnson: "We've got a lot of guys that came in and kind of proved themselves to play, and that helped Coach Wilcox a ton because now he can open up his playbook a little bit and throw those out there. I think he feels real comfortable."