FRISCO -- Charles Tapper's energy level has been so high during the first week of organized team activities that members of the coaching staff have told him to turn it down a notch.

"I'm at full-throttle, full-go," Tapper said Wednesday, "so I'm out there going 110 [miles per hour] and they're like, 'Tap, you might want to slow it down and just go 100. Don't be on the ground, diving and everything.' I'm trying to tone it down a little bit now."

The second-year defensive end missed his entire rookie season with a back injury. Tapper, a fourth-round pick, said before last season he had a stress fracture in his L5 vertebra, often called a "pars defect."

But he was cleared by doctors a week after Dallas' playoff loss to the Green Bay Packers.

Tapper said hearing that he was able to return "was like an angel was sent down from heaven."

The Cowboys' first-team defensive line in their base package Wednesday was David Irving at left end, Taco Charlton at right end and Maliek Collins and Cedric Thornton at the tackles. But when they went to their pass-situation front, Tapper was at right end and Charlton moved inside to tackle.

"It's freaky," Tapper said of lining up next to Charlton, the Cowboys' first-round pick. "We have a scary front. I can't wait to get to camp and really be able to put the pads on and see what our moves really can do."

Tapper has set some lofty goals for his first season: earn a spot in the rotation, and then break Michael Strahan's single-season sack record of 22.5.

No Cowboys player has recorded more than eight sacks in any of the past three seasons.

"Coach always [talks about] high expectations, high standards," Tapper said, "so right now I'm going for whatever the sack record is. You got to shoot for the stars."