If you're going to run a 3-4 defense, it's best to have a dominant nose tackle. The canonical example in recent years in the SEC is Terrence Cody, the mammoth in the middle of Alabama's 2009 national championship defensive line.
When Georgia transitioned to the 3-4 under Todd Grantham last year, the Bulldogs did not have a similar type of player. DeAngelo Tyson did his best at the nose, but he was a converted defensive end and is not really suited for the position. Most folks figured that UGA solved the problem by signing 6'3" 351 lb John Jenkins out of junior college. He has the requisite size for the position and had been playing it for years.
Jenkins unfortunately got injured last Friday at practice with what coaches called a "mild hamstring pull". He missed practice again yesterday, which has ace UGA beat writer Seth Emerson wondering how healthy Jenkins will be for the big Boise State game. Mark Richt hopes to have him 100% for the opener, but it's no guarantee.
The good news here for the Bulldogs is that sophomore Kwame Geathers has really stepped up his play. Listed at 6'6" 350 lbs, Geathers has bulked up to a size comparable to Jenkins and even many NFL nose tackles. He also was named the defensive MVP of the spring game, and that has carried forward to fall camp where coaches have praised his play.
Still, Georgia will need both guys healthy and in the rotation to accomplish their goals for this year. Geathers may be turning some heads in practice, but UGA has to hope he won't have to do everything himself come September.