COLUMBIA -- Steve Spurrier all but named a new quarterback Sunday, indicating fifth-year lightning rod Stephen Garcia will be replaced in the starting lineup.

Garcia has been erratic, throwing nine interceptions, two in Saturday's surprising 16-13 home loss to then unranked Auburn.

USC is 4-1 going into this week's home game against Kentucky, but fell from No. 10 to No. 18 in The Associated Press Top 25 poll.

"We just felt like we were winning, until last night," Spurrier said Sunday. "We were actually living through a lot of errors Stephen would make in games, as you guys (in the media) know. But we were still somehow winning the game. But we were hoping and believing that maybe those errors would go away, but they don't seem to go away. And so we have to figure out what we're going to do."

Sounds like the opposite of a vote of confidence.

Spurrier said an announcement on lineup changes will come today or Tuesday.

Garcia has thrown only four touchdown passes this season after leading the Gamecocks to the first SEC championship game appearance in program history last year.

South Carolina ranks 11th in the SEC in pass efficiency, ahead of only Kentucky.

"We have to shake up to the offense somehow," Spurrier said.

And: "We've coached Stephen, but Stephen seems to play very similarly about every game."

Sophomore Connor Shaw is the likely choice, but Spurrier said both Shaw and redshirt freshman Dylan Thompson, who has not thrown a pass in a college game, have looked good during Monday scrimmages.

Shaw earned a start in the 2011 opener against East Carolina in Charlotte after outplaying Garcia during preseason practice but was benched in the first half. Garcia rallied the Gamecocks from a 17-0 deficit to a 56-37 win.

Shaw has completed four of 11 passes for 29 yards this season with no TD passes and no interceptions. He drew Spurrier's ire during mop-up duty against Vanderbilt on Sept. 24, missing open tight end Justice Cunningham on a drag route.

Supplementing Shaw or Thompson with a Wildcat formation featuring Bruce Ellington is likely. But Ellington, a former Berkeley High QB, has rushed for only seven yards on six carries this season.

Other issues

Poor quarterback play isn't South Carolina's only problem on offense.

The Gamecocks were 2-for-10 on third-down conversions against Auburn's young and previously shredded defense.

Running back Marcus Lattimore has drawn Spurrier criticism each of the last two games, for a pair of penalties against Vanderbilt and two fumbles against Auburn (one lost, one recovered by tackle Rokevious Watkins).

Auburn ran 92 plays, 40 more than USC -- a staggering difference for a Spurrier-run offense.

"It's a combination of things," Spurrier said. "We're not blocking very well, we're not throwing very well and not making some third downs. And when you do that, you don't have a very good offense."

Nunn's injury

Spurrier said the back injury that kept starting left tackle Kyle Nunn out against Auburn might be "serious."

Freshman Mike Matulis started for Nunn but was benched after giving up a sack. Redshirt freshman Cody Gibson then came in at right tackle with Watkins flipping to left tackle.

Matulis and Gibson likely will split time against Kentucky, Spurrier said.