Coach Dan Mullen told reporters on Monday that Richardson had been cleared to practice that Thursday after suffering a concussion against Georgia on Oct. 30. He then injured his knee on Friday and received medical treatment Saturday morning.
Richardson, a freshman, dressed for the game against South Carolina in case of emergency, but he did not participate. He is expected to practice Monday.
Emory Jones started against the Gamecocks, completing 17 of 30 passes for 258 yards, two touchdowns and one interception.
But the Florida offense struggled overall, rushing for only 82 yards on 26 carries, and converting just 3 of 10 attempts on third down.
The loss dropped the Gators to 4-5 this season.
On Monday morning, Mullen announced that he'd fired defensive coordinator Todd Grantham and offensive line coach John Hevesy.
Linebackers coach Christian Robinson was given playcalling duties on defense, while assistant Michael Sollenne was promoted to offensive line for the rest of the year.
Mullen said Monday that firing Grantham and Hevesy was a tough decision that he felt had to be made given the inconsistency of the defense and offensive line.
"It's always hard," he said. "Those guys are friends of mine. I have a lot of respect for them. Both excellent football coaches ... But my responsibility as the head coach is to do what's best for the Florida Gators. That comes above it all. "
Mullen said he knew he would eventually be making those changes, so rather than wait he decided to do it now. The idea, he said, was to "get us headed in the direction we're going into the future" and "go search for who we're going to replace
Mullen said that he was not pressured to fire either coach by director of athletics Scott Stricklin, and that the decision was his alone.
Mullen took responsibility for the current state of the program.
"My job is to make sure we perform and this team plays to the Gator standard, which we're not doing right now," he said. "It's my responsibility to find a way to fix that."
Coming off an appearance in last year's SEC championship game, Mullen was given a three-year contract extension and a raise to $7.6 million a year in June.
On Monday, he was asked whether he'd spoken to Stricklin about whether he'd be given the opportunity to return next season.
"He's confident we'll get this fixed," Mullen said.
Florida, which needs two wins to reach bowl eligibility, hosts Samford (3-5) on Saturday.
Neither of the Gators' final two opponents -- Missouri and Florida State -- are currently above .500.