Nebraska starting quarterback Tanner Lee is in concussion protocol and his status for Saturday's game against Penn State won't be known until later in the week, Cornhuskers head coach Mike Riley said Monday.

Lee, a junior who has thrown for 2,539 yards and 18 touchdowns in 10 games this season, suffered a concussion late in the first half of Nebraska's 54-21 loss at Minnesota. He was replaced by redshirt freshman Patrick O'Brien, who was playing in only his third career game.

"I don't rule him in or out; he's in that protocol," Riley said of Lee at his weekly news conference. "That's a day-to-day thing that only the medical people will come back and say if and when he's cleared. The time line on it, I don't know."

O'Brien practiced Monday as if he were the starter, Riley said. O'Brien completed 12 of 18 passes against the Golden Gophers but was sacked six times. Riley said he'd probably be working with a smaller package of plays if he starts against the Nittany Lions.

"We're obviously going to be playing a good defensive front that we're going to have to block and execute against," Riley said, "so less may be more in a game like this for our new quarterback, if indeed he is our quarterback."

The Cornhuskers (4-6, 3-4 Big Ten) lost Saturday for the fourth time in five games. They allowed a 100-yard kickoff return to open the game and yielded 409 rushing yards to the Golden Gophers, whose quarterback, Demry Croft, ran for 183 yards and three touchdowns.

Penn State (8-2, 5-2), ranked No. 13 this week, has struggled in the running game the last three weeks, and Heisman Trophy candidate Saquon Barkley has gained just 142 yards during that stretch. Riley said, however, that there is much concern facing Barkley.

"There is no doubt about it," he said. "We have just come through a game [allowing] 400 rushing yards, and we are playing a back like that, so we've got a big job ahead of us."

Riley said Barkley was "definitely in the discussion" for the Heisman Trophy although he acknowledged he didn't know enough about the other candidates to know whether he is the best player.

"But I would like to see better," he said.

As for quarterback Trace McSorley, Riley sounded as if he's been a fan since watching McSorley lead Penn State's second-half comeback in its victory over Wisconsin for the 2016 Big Ten championship.

"I think McSorley is really a versatile, competitive guy who makes plays on his feet, on the run, and throwing," he said. "As I have watched him through the years, he's never out. Their comeback in the championship game was interesting, and I thought his play was outstanding in that game, so I have a lot of admiration for how he plays."

Nittany Notes

Penn State's game against Nebraska will start at 4 p.m. and will be televised by FS1. The Big Ten said the Lions' final regular-season game at Maryland on Nov. 25 will kick off at either 3:30 or 3:45 p.m., with final time and television arrangements announced no later than Sunday.