Minnesota Vikings running back Chuck Muncie, recently reinstated after a one-year suspension for drug problems, has been suspended for Sunday's opening game against the San Francisco 49ers because he missed two therapy sessions, National Football League Commissioner Pete Rozelle announced yesterday.

Rozelle said in a statement that Muncie had violated one of the conditions of his reinstatement July 18 by not attending two after-care therapy sessions within the past week and giving no notice he would not appear.

Immediately after Muncie was reinstated by Rozelle, the San Diego Chargers traded him to the Vikings.

Muncie was not at practice yesterday, but the Vikings issued a statement from him that said, in part, "I know I should have handled this situation better. I guess you could say I have reasons for missing the meetings, but no excuses . . . after receiving the suspension I know I will work extremely hard at making all the meetings in the future."

Also, it was reported that Vikings rookie Tim Newton, who was expected to start at nose tackle in the opener, was ticketed for possession of marijuana in Minneapolis Thursday night. The charge is a petty misdemeanor and Newton will have seven days to decide whether to plead guilty and pay a $100 fine or plead innocent and appear in court . . .

New Philadelphia Eagles owner Norman Braman, who has predicted that his team will make the NFL playoffs this season, is offering $10,000 bonuses if that happens.

Besides players, the offer includes coaches, trainers and anyone else directly connected with the football operation, according to Eagles General Manager Harry Gamble, meaning that if the Eagles do win a playoff berth, it will cost Braman about $750,000 . . .

Mark Clayton, the Miami Dolphins' record-setting wide receiver, has signed a new contract with the team, ending speculation he would walk out before this Sunday's season opener in Houston. The contract is a four-year deal worth a reported $1.4 million.