Senior left tackle Stephon Heyer, Maryland's top returning offensive lineman and most experienced starter on offense, tore the anterior cruciate ligament in his left knee in practice Saturday, the Baltimore Sun reported.

Team spokesman Greg Creese said doctors are waiting for swelling to go down before the team's orthopedic surgeon, Craig Bennett, can operate. It is not immediately known if Heyer will miss the entire season, but as a true senior, he has one year of eligibility remaining.

Maryland coach Ralph Friedgen said Heyer was in the middle of a two-on-two drill when Temple transfer Rick Costa knocked him over backwards.

"When I watched him, I didn't think much of it," Friedgen told The Sun.

Heyer, who had surgery on his right knee last season, was Maryland's top pass protector last year and would have entered the season with 24 straight starts, according to The Sun. His absence will be a setback to a young offensive line that will have to protect an inexperienced quarterback. Sam Hollenbach, the frontrunner, only has one start. Without Heyer, nobody on the line has more than sophomore experience. Second-year freshman Dane Randolph, a former standout defensive end at Wilde Lake, is Heyer's backup, the Sun said.

Friedgen also told The Sun reserve right tackle Scott Burley hurt his back and felt pain in his leg. The two injuries left two freshmen -- Jared Gaither and Zach Marshall -- at second string. Friedgen said he would consider moving Randolph to right tackle and Burley to left, if he's healthy.

"What do I do?" Friedgen said. "Do I cut off all contact drills and never get better? & It will allow us to get more reps to Gaither and Dane Randolph, get them better. Maybe in the end we'll be a better team because of it, who knows?"

Fullback Matt Deese had surgery last week to remove cartilage in his knee and will be out two weeks. Junior cornerback Josh Wilson left practice Sunday with a laceration on his left leg and is day-to-day, according to The Sun.