JACKSONVILLE, Fla. — Defensive end Reggie Hayward spent most of last season on injured reserve, watching helplessly as the Jacksonville Jaguars struggled to pressure quarterbacks, bottle up running backs and make open-field tackles.

He knew changes were coming. He just didn't expect this many.

The Jaguars debuted their revamped defense yesterday as they began a three-day minicamp designed to give rookies a taste of the team's playbook and practice ways. It also gave Hayward and other veterans a chance to meet and greet several new teammates, especially on the defensive side of the ball.

"You knew they were going to do something," Hayward said. "They had to do something. I was a little surprised they did so much. But I guess when you have an area that needs rebuilding, and if you want to do it right, you might as well overhaul it."

The Jaguars certainly did that. They might not be done, either.

Free agent safety Darren Sharper, who helped New Orleans win the Super Bowl in February, visited Jacksonville earlier this week and could bolster an inexperienced secondary.

It would be another move to retool a unit that ranked 23rd in total defense last season, gave up nearly 400 points and finished with an NFL-worst 14 sacks.

"We're looking for some energy, looking for some guys who are able to get the job done," cornerback Rashean Mathis said. "If we have to find that somewhere else than what we already have, then we're willing to do that. That's how teams get better every year. Teams get better by getting guys that aren't on their squad. That's what we need."

Jacksonville began the defensive makeover by signing free agent defensive end Aaron Kampman in March. The two-time Pro Bowler signed a four-year contract worth $26 million and expects to be ready for training camp despite knee surgery in December.

The Jags fired defensive line coach Ted Monachino, released veteran defensive lineman Rob Meier and traded underachieving end Quentin Groves. They hired fiery assistant Joe Cullen, drafted four linemen and then traded for veteran middle linebacker Kirk Morrison.

They made several more moves after the draft, including parting ways with two-time Pro Bowl defensive tackle John Henderson and starting linebacker Clint Ingram.

"We want guys that are playing with their hair on fire," coach Jack Del Rio said. "We want guys that are playing with tremendous passion and aggressiveness. That's what we've defined it as, and we're going to prop up guys that do it that way."

Jacksonville alternated defensive schemes in 2009, but plans to stick to a conventional 4-3 alignment this fall — a welcome change for players who never really got comfortable with the back-and-forth adjustments.

"We're back to the basics," Mathis said. "We're back to what we've been doing since Jack's first day here, and I think it's going to help out a lot. We know we're not bouncing around. We're know we're actually going to run a 4-3 regardless of what happens, good or bad, and we're going to stick with it.

Jacksonville used its first four draft picks on defensive linemen in hopes of improving the team's pass rush and its defensive identity.

The Jaguars selected California defensive tackle Tyson Alualu with the 10th overall pick. The Saint Louis and California alum got a warm reception yesterday, with fans chanting his name as he walked onto the practice field.

They chose Louisiana Tech defensive tackle D'Anthony Smith in the third round, then picked up Central Arkansas defensive end Larry Hart and Murray State defensive end Austen Lane in the fifth.