Richt thanked the school's academic and athletic administration for the milestone.
"I think it's great," he said. "You hope that that happens, but there is a reason why it's the first time in a long time. It's not an exact science."
Knox won't be allowed to have full contact until next week because NCAA rules require him to go through the five-day acclimatization period his teammates have already completed.
MOVING UP: Redshirt freshman Tony Wilson isn't the biggest of the Bulldogs' receivers. In fact, the 5-11, 190-pounder is bigger only than Mikey Henderson, but he's plenty tough, offensive coordinator Mike Bobo said.
"He plays very physical," Bobo said. "I think he's brought an attitude to the receivers of being more physical. You've got to have guys like that, not afraid to put their face in there. I'm real pleased with his progress."
Wilson and cornerback Ramarcus Brown got into practice fight early this week.
"He's talented No. 1, but he's also our most physical receiver right now, and that's going to go a long way," Richt said.
INJURY UPDATE: Offensive lineman Chester Adams (ankle) missed practice Friday. Tight end Tripp Chandler (ribs), Henderson (hip) and defensive lineman Brandon Wood were in green, no-contact jerseys. Adams, Chandler and Henderson aren't expected back until Monday.
True freshman Clint Boling, 6-5, 290, was lined up as the starting right tackle in Adams' place.
"He's competing for a starting job," Richt said. "He's got ability; he's pretty sharp; he's picking it up the best he can. We're so thin, true freshmen are making hay."
"Clint is going to have to get ready to play," Bobo said. "Is he ready? No, but he's all we've got."
SWELTERING: The temperature reached 103 degrees as Georgia practiced Friday, and Richt is considering moving today's afternoon scrimmage to the evening.
"It's pretty brutal out there," Richt said. "It showed today. It's rough out there. It's as hot as I can remember it."
Georgia will hold a special teams scrimmage this morning.