Injured in the Green Bay Packers' preseason loss to the Carolina Panthers, Saturday night, offensive guard Marco Rivera has been diagnosed with a sprained medial collateral ligament.

"It's not as bad as we originally thought," GM/Head Coach Mike Sherman said after the game, "but it's still serious."

Rivera suffered the injury when a player fell into his left knee on the Packers' second possession. After being examined on the field, he walked off with some assistance from the Packers' training staff.

Rivera is scheduled to undergo an MRI Sunday, at which point the full extent of his injury will be better understood.

"The doctors say there could be a chance he could be ready for the Minnesota game (Sept. 7), believe it or not," Sherman said. "When he has his MRI, we will have a clearer picture of where he is."

Rivera isn't a stranger to MCL injuries. He played through tears in both knees last season and was awarded Pro Bowl honors.

"If there's any way Marco can play, he'll play," center Mike Flanagan said. "He's one of the toughest guys in this game."