Manny Diaz understands the importance of preparation, that’s why he was hired this offseason to rebuild a Texas defense that lost its swagger.

Diaz was known for having the toughest defense in the SEC to prepare for, with coaches around the conference dreading a date with Mississippi State. The first-year Texas defensive coordinator, though, is still working to convince the Longhorns that preparation is everything.

And it certainly will be this year, with Diaz looking to send at least 22 players onto the field in the first quarter of Texas’ season-opener against Rice on Sept. 3. He’s stressed the importance of those 22 being prepared for anything.

But while Diaz says he wants 22 players in the rotation, he hasn’t quite found them all — yet.

“We’re not at 22,” Diaz said. “We’re probably maybe halfway there, past the first 11 — and even the first 11 is still in flux.

That’s what obsesses us right now. We’re really looking for people that we can really put across that line to go play in a game.

What we try to make the point of now, when roll guys between the first team and second team, there’s no first team or second team when we go play. Everybody that runs across the field is a Texas Longhorn.”

The coaching staff refused to release a depth chart in the spring and fall, mainly because they could never decide one. But the coaches also wanted to instill a sense of urgency with the team, driving out any complacency and replacing it with constant competition.

As Texas learned a season ago when they were ranked No. 4 in the coach’s preseason poll before suffering through a 5-7 campaign: It doesn’t matter where you start, but where you finish.

Blurring the line between starter and backup has been one of Diaz’s major teaching points so far. He knows from experience just how critical it is for a defense to have the depth necessary to take on the unexpected.

During Mississippi State’s season opener in 2010, Diaz lost his starting cornerback and starting linebacker in the first quarter, and found his third-string linebacker playing more than 50 snaps.

Diaz’s lesson to the players then and now? Be ready to play.

“Forget about the batting order, because once the game starts, it’s chaos,” Diaz said. “That’s just what happens.”

While Diaz may not have had the depth at Mississippi State to cycle 22 defenders in each game, his arsenal at Texas is large enough to play that way.

Diaz’s defense is pressure oriented, so the more fresh bodies that are on the field at a time, the more aggressive the coach can be. With Diaz planning to rotate 22 players, playing time for veterans could be cut down. But junior defense end Alex Okafor understands the benefits of a deep bench.

“With this defense, we’re coming at you all the time, so it’s going to be hard for anybody to just play a full game,” Okafor said. “So we need a backup at every single position for us to be able to do what we want out there and bring heat continuously.”

For a Longhorns defense that saw entirely too much time on the field in 2010, the opportunity to have enough in the tank for the fourth quarter is a welcome sight. A year ago, the defense was constantly worn down by the end of the game as opponents were able to keep the ball on the ground with the Longhorns playing from behind.

Now, by rotating in more defenders, Diaz hopes the results will pay off in the long run. And his players agree.

“That definitely will keep us fresh,” said sophomore defensive end Jackson Jeffcoat. “It will help everybody be able to go 100 percent every play. Just rolling guys in, everybody’s going to be healthy and fresh to go.”

But for Diaz’ plan to be successful, he will have to get production out of everyone — not just the starters. So far, the non-starters have been performing well in closed scrimmages. But they haven’t been tested in the games that count, and they will have to rise to the occasion when their number is called on Sept. 3.

“That’s definitely a big thing,” said sophomore linebacker Jordan Hicks. “The [backup] have to step up and they have been.”

Though Diaz may feel like he needs 22 players to see time on the field to be successful, he’ll need to 22 who are ready to go from the time they step on the turf.

So, are the Longhorns deep enough on defense?

“I feel like we are,” Jeffcoat said. “A lot of guys have been able to roll in and take reps with the [starters], take reps with the [backup], and that’s helped us out a lot.”