Wilcox likes to base his defense on field position, down and distance, plus the opposing offense's personnel. The problem is that Montana utilizes a hurry-up offense that leaves the defense mere seconds to evaluate and react to field position, down and distance and personnel.
That means sending in multiple substitutes between snaps is going to be much more difficult than usual vs. the fast-paced Grizzlies.
"Absolutely," Wilcox said this week. "With the tempo they do limit your subs. That's one thing we have to be ready for, obviously, and we have been stressing that for two weeks."
Montana wastes no time between the end of one play and the start of another. That's why the Grizzlies often squeeze in 90 snaps per game — about two dozen more than most teams. Anticipating their fast pace is no problem; preparing for it is.
"It's very hard to simulate during practice," Wilcox conceded, "because it's something they do every day. It's part of their program. It's how they operate. It's an up-tempo pace, and we have to be ready to handle that."
Opposing defenses face obvious problems: Sometimes a defender who is tired or playing poorly must stay on the field an extra snap or two before a sub can rush onto the field. Sometimes a run-stuffer remains in the lineup because the third-down pass rusher was slow getting into the huddle to replace him. Basically, Montana's pace limits the defense's substitutions.
Wilcox put it this way: "What that does is, sometimes if you want to sub and they are going up-tempo, you are not able to just because you don't want to be running in and out while they are snapping the ball."
That means Tennessee may have to use fewer defenders who specialize in certain down-and-distance situations and more guys who are roughly as solid against the pass as against the run.
"We have to be able to play groups to all their personnel groups," Wilcox said. "We can't always one-for-one sub them if they're going at that up-tempo. It can (limit what Tennessee does). We'll see how fast they are going."
Montana is not the first fast-paced offense Wilcox has tried to stop in his brief tenure at Tennessee. He faced Oregon last fall, a team that torched his stop unit for 447 yards in a 48-13 beat-down that stands as the most lopsided Vol loss in Neyland Stadium history.
Asked if that humbling experience might be a benefit for Vol defenders, Wilcox replied: "It can be for the players that played in the game."
Unfortunately for Tennessee, most of its 2011 defensive starters were not playing significant roles this time last year. Three freshman starters — linebacker Curt Maggitt, linebacker A.J. Johnson and cornerback Justin Coleman — were not even out of high school this time last year. Facing a hurry-up offense in Game 1 will make adjusting to the speed of college football especially difficult for them.
"You can tell them every 12 to 13 seconds they are running a play and you can simulate it out here at practice by doing up-tempo fastball formations. That's something we've done for a while now," Wilcox said. "You can talk about it all you want (but it isn't until) you're in that environment that you really get exposed to it."
In addition to Montana's brisk tempo, Tennessee's defensive scheme and substitution pattern may be limited by having three freshman starters.
"We'll see," Wilcox said. "It's always a fine line as to whether you're carrying too much or not enough. We're always going to ride that line and make sure our guys play fast."