"I should have stayed at home," he said.
Johnson hopes to be back for the Sept. 22 Alabama game.
Cornerback Bryan Evans hyperextended his knee Tuesday and was very limited in Wednesday's practice. Evans said Wednesday that he will play, but Richt called him "questionable."
Safety Kelin Johnson said Wednesday he will play, but Richt also listed him as questionable.
Wide receiver Mikey Henderson will wear a small cast on his left thumb during the game but doesn't expect it to affect his ability to catch punts and passes.
Richt would not say if any changes in the starting lineup are expected this week.
Miller "is doing all right, he'll be fine," Richt said.
"The defense has to balance up and play honest," running backs coach Tony Ball said. "They can't read the flow of that one guy like teams would normally do. With those two in there, it gives you matchup problems on defense."
However, offensive coordinator Mike Bobo said he will be hesitant to use the grouping this week because of depth issues at tailback. Seniors Kregg Lumpkin and Jason Johnson are out due to hand injuries. Moreno has a hand injury that won't keep him out of the game but has caused him to be slightly limited in practice this week.
NATIONALLY RANKED: Dublin's Brian Mimbs is third in the SEC and 29th in the nation in punting with a 42.7-yard average. Mimbs averaged 43 yards on five kicks last week against South Carolina with a long of 50.
"I progressed from the first game," he said. "I feel like I'm beginning to hit it a little better, getting a little more confident. Each week I want to hit the ball a little better than I did the previous week."