Georgia prop Levan Chilachava has been ruled out of RWC 2015 because of a leg injury sustained in Friday night's match against New Zealand in Cardiff.
Chilachava came off early in the second half of the All Blacks match after injuring his left calf.
Georgia's coach, Milton Haig, confirmed the Toulon-based player will miss the rest of England 2015.
"He's presented with a new tear in his leg," Haig said. "He's had problems with his calf all year with Toulon, so we'll have to bring in a replacement for him."
On Sunday evening Haig said the team had yet to confirm a replacement.
Meanwhile, Georgia full-back Merab Kvirikashvili says his hamstring is almost back to 100 per cent after he was rested for the All Blacks game.
"I think it’s 98 per cent good," he said. "I’ve been able to rest a little more than three days now. Today was my first day back in training and there was no pain or discomfort, so I am sure I will be ready (for Namibia)."
Georgia's captain, Mamuka Gorgodze, has also been troubled by injuries to both knees but will be ready to face Namibia.
"He sat out training this morning because he’s got a little twinge in his knee," Haig said. "But more importantly, we wanted to rest him a little because he’s played a lot of minutes so far, and you know how Mamuka plays: he’s pretty combative and puts his body on the line.
"A lot of people asked why he played against New Zealand and I said it's because he’s our captain. In my view, a captain should start every game if he is able to.
"We knew it would be like this and that we would have to manage him in this last week. Everything that he’s done previously starts to come home on him and his body gets a bit sore, but he’ll get himself up for one more game and lead us with pride again."