Norman, Okla. ? The search for All-American free safety Quinton Carter’s replacement has Oklahoma considering a shuffle in its defensive lineup.

Sophomore Tony Jefferson, the Sooners’ starting nickel back for most of last season, is experimenting with a move to the back end of the defense early in training camp as defensive coordinator Brent Venables tries to identify the best combination to put out on the field.

Jefferson was chosen by coaches as the Big 12’s co-defensive freshman of the year last season, when he started nine games and finished with 65 tackles, two sacks and two interceptions. He could be stepping into bigger shoes if he ends up as the successor to Carter, who was picked to the Associated Press All-America team last season after recording 95 tackles and four interceptions.

“Tony’s already proved a year ago he’s a guy that makes the tough plays,” coach Bob Stoops said. “We’re seeing if that’ll continue at that spot as well.”

Jefferson’s potential move would also create an opening for sophomore Corey Nelson to get onto the field in the hybrid outside linebacker/nickel back role. Nelson was a highly regarded freshman but couldn’t get playing time on occasion last season because there wasn’t a spot for him.

“What we’re looking for more than anything is to find ways to get players that over the last year have shown us a knack for showing up at the football and making plays. They’re instinctive guys,” Venables said.

“They’re good football players, and I think we’d be negligent not to find ways to get them on the field, to find what they’re comfortable with.”

For now, the move is only a tryout. The Sooners donned pads for the first time Monday and are more than three weeks away from the season opener Sept. 3 against Tulsa. So, Jefferson is also continuing to take snaps at his familiar spot in case he needs to move back.

Junior Javon Harris and senior Sam Proctor, who started 10 games at strong safety in 2009, are also in the running for Carter’s old spot.

Jefferson isn’t new to the position. He played safety at Eastlake (Calif.) High School.