LINCOLN, Neb. -- Nebraska defensive end Randy Gregory underwent arthroscopic surgery on his left knee on Sunday and likely will not play this week against McNeese State, coach Bo Pelini said.

Randy Gregory, who led the Huskers with 10.5 sacks last season, likely will return against Fresno State on Sept. 13. Jesse Johnson/USA TODAY Sports

Gregory, a junior returning first-team All-Big Ten honoree, suffered the injury during the opening defensive series of the Huskers' 55-7 win on Saturday over Florida Atlantic.

"An old injury," Pelini said, "something that flared up on him, and they went in and fixed it."

The coach said he considered Gregory as probable for Nebraska's first road game, Sept. 13 against Fresno State.

He led the Huskers with 10.5 sacks last year. Walk-on Jack Gangwish primarily played in Gregory's place against the Owls.