The No. 10 Bulldogs (5-0, 2-0 SEC) take on the No. 13 Volunteers (4-1, 0-1 SEC) Saturday at 7:45 p.m. in Sanford Stadium.
Coutu was scheduled to have an MRI on Thursday evening. He was injured earlier in the day attempting a new onside kick technique.
"It put his leg in a little different position than he's used to," Richt said. "I think it's something that he saw in the NFL. Somebody popped one up real high, and he was trying to do that. I noticed that kick. It popped way up. It was perfect. I noticed it was new, but I didn't think anything of it."
Coutu injured the back of his knee on the play, Richt said.
"I'm not exactly sure what it was," Richt said.
Coutu, a strong candidate for the Lou Groza Award, which goes to the nation's top kicker, is 7-for-8 on field goals and 15-for-15 on extra points this season.
Junior Andy Bailey, a scholarship kicker who hasn't attempted a field goal since 2004, will handle the Bulldogs' kickoffs and extra points. Walk-on Ben Wilson will kick off.
"The bad news is Coutu, but the good news is Bailey has been kicking beautifully," Richt said. "On Tuesday, I thought (Bailey) kicked fantastic."
Bailey, a native of Athens, Tenn., hit 14-of-20 field goals as a freshman and had a long of 46 yards. Players aren't available for comment after Thursday practices.