South Carolina quarterback Connor Shaw will return from a sprained knee at some point this season, but it won’t be this week.

Backup quarterback Dylan Thompson will start Saturday when the No. 21 Gamecocks play at No. 5 Missouri, USC coach Steve Spurrier said during his Tuesday afternoon news conference. Spurrier said Shaw could possibly dress and make the trip to Missouri, but the game belongs to Thompson.

“He may be able to dress and get backup,” Spurrier said of Shaw. “We don’t know, but Dylan is definitely going to start the game, and it’ll be his game to go with.”

That means the biggest game of the SEC East season will be decided by a pair of backup quarterbacks. Matty Mauk led Missouri to a win over Florida last weekend despite the absence of starting quarterback James Franklin. For USC, Thompson is used to the pressure.

Thompson led the Gamecocks to their biggest win of the 2012 season, a 27-17 win over Clemson. In Shaw’s absence, Thompson completed 23 of 41 passes for 310 yards, three touchdowns and one interception, including the clinching 6-yard touchdown pass to Bruce Ellington with 4:17 left in the fourth quarter.

Earlier this season, Thompson also led USC to a 28-25 win at Central Florida after Shaw was knocked out of the game on the opening possession with a sprained shoulder.

“I think Dylan’s ready to go,” Spurrier said. “He hasn’t had the opportunity for us to say, ‘Hey, this is your game, let’s go play.’ He’ll prepare as hard as he can this week. He will be ready to go, and he’ll give it his best shot. We know that. This is his time this year, it’s coming up.”

This may be Thompson’s week, but it’s still Shaw’s season. Spurrier said the senior quarterback may be able to run around some by the end of this week. Shaw is expected to make a full recovery by mid-November.

“The doctors, the trainers feel like a couple of weeks, two to three weeks, he may be close to a hundred percent on that thing,” Spurrier said.

Quarles ‘probably doubtful’

South Carolina could play without more than its starting quarterback Saturday.

A rash of sprained knees and ankles has gone through the program in the past couple weeks. Most notable, defensive tackle Kelcy Quarles walked off the field at Neyland Stadium hobbled on crutches, unable to put pressure on his sprained knee.

“Kelcy is coming around,” Spurrier said Tuesday. “… He’s probably doubtful right now, but he’s walking around OK. He’s off his crutches. If he’s not back this week, he should be back maybe in two weeks.”

Quarles leads USC with five sacks and seven tackles for loss.

Also included in the injury report is a pair of offensive linemen. Guard Ronald Patrick is questionable this week and could play, but center Cody Waldrop is doubtful. Both have ankle sprains.

A ‘new fad’

Spurrier was stunned the SEC league office confirmed the on-field ruling that Tennessee running back Rajion Neal threw a pass instead of fumbling at the end of Saturday’s first half.

Neal deliberately threw the ball away when USC defensive end Jadeveon Clowney wrapped him up in the backfield. It looked like a fumble, and the play would have set USC up in field goal range — potentially the difference in a two-point loss.

After watching game film, the longtime coach said he saw something for the first time.

“I didn’t even know a running back, if he’s running a sweep and about to have a 20-yard loss, he ought to just throw the ball past the line of scrimmage,” Spurrier said. “I never taught a guy to do that, but maybe that’s a new fad. He’s a passer, he should just throw it away. Maybe. I may need to get clarified on all those rules.

“None of us have ever seen that, I don’t believe. The running back tossed the ball.”

Follow South Carolina beat writer Ryan Wood on Twitter @rwood_SC.