Oklahoma State senior linebacker Orie Lemon suffered a serious knee injury earlier this week that could cause him to miss the upcoming season.
Sources told ESPN.com that Lemon tore an ACL in practice on Monday, although a report in the Tulsa World indicated that he didn't walk with a noticeable limp when he left practice that day.
There has been no official confirmation from within the Oklahoma State football program about the injury, which comes only days before the No. 9 Cowboys' crucial season-opening game against No. 13 Georgia in Stillwater on Saturday.
Coach Mike Gundy was asked by a caller on his weekly radio show Tuesday night about the health of Lemon. He did not specifically acknowledge that Lemon was injured.
"If a guy goes down, then another guy has got to play 10 or 15 more plays a game," Gundy said on his show.
Lemon started all 13 games for the Cowboys last season and was second on the team with 90 tackles. He also deflected eight passes and made four tackles for losses.
Lemon has not used a redshirt season in his college career. If he can't play this season, he potentially could return as a fifth-year senior in 2010.
If Lemon can't play against Georgia, he would likely be replaced by senior linebacker Donald Booker, a special-teams standout and pass-rushing specialist who has never started a college game.
The 5-foot-11, 235-pound Booker produced 32 tackles last season. He previously was an All-American linebacker at Navarro (Texas) Junior College, where he notched 161 tackles to lead all junior colleges in 2007.
Tim Griffin covers college football for ESPN.com. You may contact him at email@example.com