The Tigers found out shortly after their stunning, 84-75 loss to South Carolina on Saturday that starter Anfernee McLemore was lost for the season after a horrific injury late in the first half.
"Now, we're down to eight guys," Auburn coach Bruce Pearl said.
The Tigers (23-4, 11-3 SEC) were already one of the smallest teams in the country - "We're 305th in size," Pearl said - and will go the rest of the year minus their top low-post presence in the 6-foot-7 McLemore, who fractured his tibia and dislocated his left ankle.
Pearl said McLemore will travel back with the team and most likely have surgery Sunday. McLemore will need up to six months to recover.
"It's just sad," Auburn forward Desean Murray said.
Pearl said he told his team they can't worry about factors out of their control, such as McLemore's injury. Everyone left on their schedule will be gunning for the first-place Tigers, and it's up to his players, Pearl said, to find a way to succeed.
"We've got to clear our heads," Murray said, "and bring another level of focus to practice."
Auburn had lost its focus early in this one as South Carolina used a 21-1 first-half run to move in front by 26 points.
Frank Booker scored 19 points for South Carolina, which ended its six-game losing streak.
Auburn blocked out McLemore's injury in the second half and cut its big deficit down to 64-59 with just under seven minutes left.
But South Carolina scored the next seven points to restore the double-digit lead, and Auburn could get no closer than six points the rest of the way.
South Carolina beat a top-10 program for the third straight season and defeated its first top-10 team at home since taking out No. 1 Kentucky in January 2010.
Chris Silva had 14 points and 11 rebounds for South Carolina, his sixth double-double of the season.
South Carolina coach Frank Martin said his team has worked hard this season but struggled to close out tight games.
"We've got to embrace this moment," he said.
Mustapha Heron led Auburn with 16 points, just four of those coming in the second half. Brown, the Tigers' leading scorer this season, was held to 10 points (six fewer than his average) on 3-of-16 shooting.
Auburn has been the surprise of the SEC season so far. Things may get harder with McLemore out.
McLemore came down hard late in the first half while on defense. He immediately began shouting and medical personnel quickly surrounded him underneath the basket. Auburn coach Bruce Pearl and South Carolina coach Frank Martin came out to check on the 6-foot-7 sophomore, who was diagnosed with a dislocated left ankle and taken off the court on a stretcher before being transported to a hospital for X-rays, which confirmed the severity of the injury.
Before leaving, McLemore sat up and waved at the cheering crowd.
Auburn: The Tigers' run to an SEC crown and beyond could take a dent with McLemore sidelined. The Tigers' tallest players among those in the regular rotation are 6-8 forwards Horace Spencer and Chuma Okeke. Spencer had started six games this season, while Okeke has come off the bench all season.
South Carolina: It's hard to know what's going on with the Gamecocks. They've beaten three top-25 opponents in No. 18 Kentucky, No. 20 Florida and now, the 10th-ranked Tigers. They've also lost by double digits this month against Texas A&M and Arkansas. South Carolina will need to channel the effort against Auburn if it hopes to make some noise down the stretch.
Three starters from last year's Final Four team in Sindarius Thornwell, Duane Notice and P.J. Dozier returned to receive their rings from last year's NCAA Tournament run. The trio was around at practice on Friday and lit into the Gamecocks for their poor play at times this season. "Here they come with a bag of energy and they put it to us," Booker said. "And it carried over."
South Carolina reserve guard Kory Holden has left the Gamecocks. South Carolina coach Frank Martin announced Holden's decision shortly before tip-off. Holden missed the past 11 games with a hamstring injury.
Auburn returns home to play in-state rival Alabama on Wednesday night.
South Carolina ends a two-game homestand on Wednesday night against Georgia.
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