South Carolina is 6-1, ranked as high as No. 12 in the latest polls and controls its own destiny in the SEC East. Still, as of this afternoon, its 2011 campaign is officially a season on the brink: As feared, Herculean running back Marcus Lattimore is out for the rest of the season with a knee injury he suffered in Saturday's 14-12 win at Mississippi State, robbing the Gamecocks of one of the most feared weapons in the country and their only reliable offensive anchor. He'll return in 2012 with two years of eligibility remaining.

For a team that's three points away from an undefeated record, Lattimore is one of the few things Carolina has had to feel consistently good about. The defense struggled through a pair of shootout wins over East Carolina and Georgia to open the season, and against Navy's triple-option attack. Senior quarterback Stephen Garcia was so erratic through the first five games that he was benched following a 16-13 loss to Auburn on Oct. 1, and subsequently booted from the team last week. His replacement, Connor Shaw, just followed up a barn-burning start against Kentucky with an uninspiring, two-interception afternoon in Starkville that goes down — for now — as the Gamecocks' worst offensive effort of the season.

Meanwhile, Lattimore has been money in the bank. Against Georgia, he churned out 174 yards on 27 carries in a 45-42 win, 94 of them with Carolina protecting a narrow fourth quarter lead. Against Navy, he accounted for 272 yards and all three Gamecock touchdowns in a come-from-behind, 24-21 win, at one point handling the ball on 11 of 15 snaps during a six-minute, 79-yard drive for what turned out to be the winning score. Against Vanderbilt, he accounted for 150 yards and both offensive touchdowns in a 21-3 win, including a career-long, 52-yard catch-and-run just before the half.

Lattimore can hold his own against any back in the country as an every-down workhorse, a short-yardage bulldozer or a receiver out of the backfield: For the second year in a row, no SEC running back has carried the ball as often, or for a greater share of his team's total offense. The only comparable talent in college football at the moment is Alabama's Trent Richardson, who has the luxury of playing opposite the nation's best defense and running behind arguably its best offensive line. For South Carolina, Lattimore is the luxury. Or at least, he was.

With Florida fading fast and a tiebreaker over Georgia in hand, the SEC East is still the Gamecocks' to lose. And as long as first-rate receiver Alshon Jeffery is on the field, there's a mismatch waiting to happen in opposing secondaries. But the passing game and the offense in general were already struggling even with Lattimore — four of the last five games have ended with 24 points or less on the board, and Lattimore supplied seven of their nine touchdowns in those games. If Carolina has any chance of maintaining its perch in the division down the stretch, the burden falls squarely on the defense.

- - -
Matt Hinton is on Facebook and Twitter: Follow him @DrSaturday.