"He possibly could be out for a while," said Spurrier after the Gamecocks' 14-12 victory over Mississippi State here on Saturday.
Lattimore was injured during the fourth quarter while blocking for slotback Bruce Ellington on a play run out of USC's wildcat formation.
Spurrier said the initial diagnosis from team physician Dr. Jeffrey Guy was a sprained left knee.
Lattimore, who did not meet with the media after the game, departed Davis Wade Stadium on crutches with a large brace and athletic tape around the knee. He is expected to have an MRI in the coming days once the swelling in the knee subsides.
While Lattimore was tended to by team medical staff, many USC players congregated around him, offering support and prayer, defensive tackle Melvin Ingram said.
"We're like a family," Ingram said. "When one of us gets hurt, it's like all of us get hurt. We want all of our brothers to be there in every battle."
Added quarterback Connor Shaw: "Whenever you have an injury like that, it's frustrating. It's scary. We're behind him, and we'll continue being positive through the week."
The Gamecocks are idle this weekend and do not play again until traveling to Tennessee on Oct. 29. Spurrier said that he is hopeful if Lattimore is not ready to play by that point, USC will at least regain the services of reserve tailback Kenny Miles. Miles has missed the last four games with a sprained wrist.
"Hopefully a sprained wrist is back in two weeks," Spurrier said. "If not, Brandon Wilds is a very good back. He's ready to go."
Wilds, a true freshman from nearby Blythewood High, would be the next in line to start. Fellow freshman tailback Shon Carson was lost for the season during the Georgia game with a knee injury. In terms of the depth chart, behind Wilds would be walk-on Josh Hinch, a Knoxville, Tenn., native who played well in the spring game in April.
Spurrier also indicated Ellington could see some time at tailback if Lattimore is unavailable indefinitely.
"If Marcus is out, we'll probably use two or three backs," Spurrier said.
Shaw said a lengthy loss of Lattimore would affect the USC offense "greatly."
Lattimore struggled against the Bulldog rush attack, netting only 39 yards on 17 carries. But his 4-yard touchdown run did tie the game at 7 in the second quarter.