Georgia Tech defensive end Antonio Simmons was given an opportunity to practice with the first-string defense, and he has taken advantage.

Simmons is subbing for starter KeShun Freeman, who is out with an undisclosed injury. Coach Paul Johnson said Tuesday that Freeman “hasn’t practiced much” but was hopeful that he’ll be available for the season opener against Boston College on Sept. 3 in Dublin. Last season, Freeman started all 12 games and had 44 tackles with two sacks and four tackles for loss.

“Antonio Simmons has had a good camp,” defensive coordinator Ted Roof said Tuesday. “He’s had a lot of production, has improved. He’s put on 20 pounds since last year, so he’s become more physical, not to be confused with physical enough.”

Simmons, a junior listed at 6-foot-3 and 235 pounds, could conceivably play in a rotation with Freeman at the rush-end position.

Simmons has the speed to be an effective edge rusher and an extra gear that enables him to “make a mistake at times and still make a play,” Roof said. Defensive-line coach Mike Pelton has been working with Simmons on his technique to provide more sturdy resistance against run blocking. Boston College figures to bring a power run game against the Yellow Jackets.

“You can’t predict when they’re going to throw the ball, so he has to do his job helping us stop the run,” Pelton said.

Simmons returned to school for the fall semester after missing the spring semester for a reason he declined to offer last week. Last season, he played in 11 games and started three, finishing with 13 tackles.

“Sometimes when you take things for granted and they get taken away from you, you realize how much they mean and what a privilege it is and not just a right,” Roof said. “I think that his perspective is more mature now and we’ve just got to keep seeing growth from all our guys.”