Prater did not participate in the Broncos' practice Saturday because of a virus and did not practice with the team this week. Fox said Prater was sent home, in part, for him to recover and in part to prevent any other players from getting sick.
The Broncos leave Sunday for New Jersey, where they will play the Seattle Seahawks in Super Bowl XLVIII.
"We've got hand washers ... all over the building," Fox said. "We sent him home, he's going to be fine for the game, hopefully he feels much better (Sunday) morning as we fly to New Jersey."
Prater led the NFL in touchbacks on kickoffs during the regular season and was 25 of 26 on field goal attempts in the regular season, including 6 of 7 from 50 or more yards, including an NFL-record 64-yarder on Dec. 8 against the Tennessee Titans.
Prater is 5 of 6 in the postseason, including a 4-for-4 performance in the AFC Championship Game this past Sunday.
Fox said the Broncos taken the requisite precautions all season when it comes to players and staff members who are ill. At one point earlier this season, Broncos head trainer Steve Antonopulos sent Fox home for a day.
"It's happened all season, happened to every team in the league," Fox said. "Guys do get sick, just like any household in America. We feel confident he'll be fine shortly."
Also, Saturday defensive tackle Sione Fua (calf) was held out of practice for the second consecutive day. All of the other Broncos players participated, including defensive Mitch Unrein (knee) and running back Knowshon Moreno (ribs), who were limited in Friday's workout.