Redskin fullback John Riggins reiterated yesterday that this could be his last season in the National Football League, especially if he feels his level of performance is deteriorating.

Riggins, who walked out on the team for a day this week over a contract dispute, also said that any decision about retirement would be affected by the Redskins' success this season.

"If we have a real bad year and I have a good year, it's still lost," he said. "I've done it twice (gained 1,000 yards) and both times the team has had losing seasons.

It's futile. It's fun when you play well and you win, but it's a job when you lose."

Riggins declined to talk about his walkout, which occurred after the club refused to guarantee the last years of his current contract. But he did say that he wouldn't expect the Redskins to continue to pay him at his current $300,000 salary level if he does not have a good season.

"No one wants to pay me at my level if I don't perform," he said. "But I feel good and I am healthy, although being realistic, I'm not going uphill anymore in my career.

"I'm leveling off, more or less. I'm okay as long as I stay at my current plateau. So far, I've had no occasion to slip down the other side.

"The first thing I'd think about regarding retirement is pride. I don't want to be on the field if I can't contribute. I've seen too many older players who have hung on and who couldn't contribute."

Riggins, who just turned 30, is beginning his ninth pro season. He is coming off his most productive year: 1,014 yards, 248 carries, a 4.1-yard rushing average, 31 receptions, five touchdowns and the 12th and 13th 100-yard-plus games of his career.

If the Redskin offense is to be effective this year, Riggins must have a good season. He is their only proven runner and could be asked to lug the ball even more than last year, although backup Clarence Harmon is expected to give him more relief than in previous years.

Yesterday, Riggins was cautiously optimistic about the team's chances. Choosing his words carefully -- "I've been known to say blunt things," he said -- he emphasized that the Redskins should be better than in 1978, but only if everything jells from the start of the season.

"Right now, there is a lot of hope and faith," he said. "I guess it's always that way. But we've got the talent to play with some of the playoff contenders. I really feel that way.

"Being realistic, we aren't a Super Bowl team. We aren't in the same class with a Dallas, even if you don't concede anything to anyone.

"I don't see any reason why we shouldn't be able to play Philadelphia and New Orleans and Green Bay, teams like that. I'm sure they have improved, too -- the gross national product keeps getting bigger every year too -- but we've come a long way since last season and made a lot of improvements.

"Now only time will tell. Exhibition games are one thing but the real test starts Sunday. We can't be smug about anyone we play. We found that out last year when we were 6-0 and things fell apart. We wound up playing at a very poor level in this league.

"We won't have an easy time with anyone. Dallas scares a lot of people just with their reputation. We used to do that but we've lost it. Now we have to get it back."

What about opening with a playoff contender like Houston?

"Well," he said, "I've been looking forward to playing them from the minute I saw they were on the schedule. A linebacker like Bob Brazile, he is one of the best, if not the best. It will give me a chance to judge myself right away, because I will have to spend a lot of time checking him.

"The game will be a real good test. It will tell us a lot about what we've got and don't got. Of course, this one game won't make a season but at least it will show the level we are playing on right now, compared to the end of last season."

What about the offensive line, which Coach Jack Pardee says is improved over last season.

"The line is definitely as good as last season," he said, "and possibly better. To make a judgment now would be premature. That's why we have the regular season."

Is he ready to play, considering the events of the past few days.

"Yes, this has been a good practice week for me," he said. "It's been such a hard camp that my legs have felt heavy, they just haven't come back.

"But they feel good now. They are light again. They should feel light. I'm a shade under 230 and I probably have less body fat than I've ever had.

"That's because of lifting. This is the first time that I've weight-lifted in the off-season and I've noticed the difference.

"I was worried about my stamina. I got really tired against Atlanta but against Cleveland last week I felt good.

"The exhibition season for me is to make sure I'm ready to play the regular schedule. I don't want to waste 80-yard runs. Well, I guess I'm not supposed to run 80 yards anymore but if I could, I wouldn't want to do it before the real season."

Riggins said he is entering the season without any preconceived notions regarding his future. He said he considers himself "a counterpuncher who reacts to what he sees. That's how I run on the football field. I see what is happening and then respond.

"I haven't thought that far ahead to make a judgment. I just have to play and do the best I can and then at the end of the year, I will re-evaluate what is going on and make a decision.

"The only thing I know right now is that it isn't fun to get beat up. I've been through that enough, although now you try to put it our of your mind.

"The only problem is, the (opponents) seem to get a lot more friendly if you have the football."

Guard Dan Nugent will undergo surgery next week on a ruptured disk in his back, a team official said yesterday. Nugent already has been placed on the injured reserve list and now will be out for the season . . . . The Redskins also have used rookie Neal Olkewicz, normally a middle linebacker, at Pete Wysocki's outside linebacker spot this week during closed practices. Another rookie, Rich Milot, has run ahead of Wysocki on the first unit. All three will play Sunday at the position . . . Pardee again refused to name his starting lineup for Sunday. Asked if it would be the same as for the final exhibition game, he said yes, but added "I've been misquoted before." All week he has tried to play down any personnel changes.