Amarlo Herrera of the Georgia Bulldogs in action against Ole Miss in this file photo.

ATHENS, Ga. - Georgia inside linebackers Michael Gilliard and Amarlo Herrera weren't exactly thrown into the fire when they ascended to the top of the depth chart after injuries to Alec Ogletree and Christian Robinson.

Thrown into a soothing swimming pool might be more accurate.

Gilliard and Herrera performed well when the opponents were outmanned Coastal Carolina and reeling Ole Miss. It should be much different for the duo this Saturday, when the Mississippi State Bulldogs invade Sanford Stadium with their punishing style of play.

"It's a big day for those guys," Georgia coach Mark Richt said Tuesday. "They are a very, very physical team."

Gilliard, a 6-foot-2, 220-pound junior from Valdosta, became a starter after Robinson went down with a chipped bone in his foot against South Carolina. Herrera, a 6-2, 231-pound freshman from the Atlanta suburb of College Park, started against the Gamecocks after Ogletree broke his foot the week before against Boise State. He got his second start last week in Oxford.

Safety Shawn Williams moved up and started alongside Gilliard against Coastal Carolina but moved back to safety last week. Richt is hoping Robinson can return for the SEC's battle of the Bulldogs, but Gilliard and Herrera are expected to play most of the way with the chore of stopping Chris Relf and Vick Ballard.

"It's going to be one of our biggest tests right here," said Gilliard, who is tied for third on the team with 19 tackles. "They're a physical team, and Relf is a very athletic quarterback. Guys like him you have to contain, and you have to put pressure on him.

"They have a very athletic offensive line, so we just have to go out there and make plays."

Relf rushed 20 times for 109 yards in MSU's 24-12 victory over Georgia last season in Starkville, while Ballard added 64 yards on 13 carries and scored touchdowns rushing and receiving. MSU averaged 214.8 rushing yards per game last season and is averaging 217.5 rushing yards through four games this year.

Ballard has rushed for 407 yards, or 101.8 per game, and has averaged 7 yards a carry.

"It always comes down to your defensive front first," Richt said. "Are you creating some kind of havoc up front and are you holding the point? If the D-linemen get moved, there aren't many linebackers in the country who could stand a big 300-pound lineman on them and then come off that block and make a play.

"If one lineman can handle our down guy and another one can get freely up on a linebacker, then we've got problems no matter who our linebackers are. The big key will be whether we can free those guys up to make some hits."

Mississippi State lost starting right guard Tobias Smith for the season on Sept. 15, when he tore his ACL in the 19-6 loss to LSU.