John Riggins said yesterday, "If I don't have a really big year this year, this will be my last one. I'll just walk away and go get to some of the other things I'd like to do with my life."

But Riggins said it with a sly grin and a twinkle in his eye because he expects a great season.

He is healthy again after walking a tightrope last winter to improve his wounded knee, balance and concentration.

Most of all, he is eager to play again after the two most frustrating and depressing years of his life. During those years he was the highest paid blocking back in the history of the National Football League, he said.

Recently, Riggins' name and $300,000-a-year salary were included in Sports Illustrated's list of the five most overpaid players in professional sports.

"Sure it makes you feel bad," Riggins said, "but it doesn't make me feel that bad because I never had a chance to show that I deserved to be paid. I never had a chance to earn what I was making. This year, I'll have that chance.

"This year we've got some imagination, and to me, that's football. I'm not trying to knock George Allen, but his offense was stagnated and he refused to change it. We were like a one-legged man in a butt-kicking contest. That just doesn't work out too well.

"Now we're doing some fun things. We've got deception. Last year, we telegraphed everything. We acted like we could blow people off the ball with an offense that was set up for Larry Brown and Charley Harraway, not John Riggins, Mike Thomas or Calvin Hill.

"We've running more complementary plays, things that look the same but the defense can't tell who's going to get the ball, or where we're going to attack. We've got some good counter plays for the fullback, the kind of things that will keep a defense honest.

"I'm a long way from a football genius, but I do know that last year there was a lot of pressure put on the offensive line and the backs because the defense knew what was coming all the time. That meant you'd have to outhorse them every time, and there are very few football teams in the league I know of who can do that.

"I just seemed to be that our theory on offense was not to lose the game, hold your own, the other team will make a mistake, we'll get it inside the 20 and we'll score from there. But football changes.

"George changed his defense all along, but not the offense. Last year I really thought it caught up with him. Even if I had stayed healthy, I don't think it would have been that different. Clarence Harmon (the rookie who replaced him) did a hell of a job. I wouldn't have made any different at all."

A year ago when Riggins came to his second Redskin training camp, he thought things would differ from the 1976 season, when he primarily blocked for Thomas. Then he looked at the playbook and saw nothing had changed.

The normally bubbling back, a man quick with a quip, went into a shell. At first, he said, he nearly walked out of camp. He stayed, but it declined all interview requests much of the season.

"I was depressed, to say the least," he said. "I just got to the point where I felt there had to be something better than just feeling miserable all the time. I wasn't too keen on the season.

"I hate to keep talking about the past, but there are somethings that should be cleared up. the offense was just not designed for the talent we had. They also told you, "This is the way you do it,' and that was it.

"It's funny, toward the end of the 1976 season I was doing pretty well, I thought I was showing some people that I really could play this game. Actually, I just decided to start doing some things my way.And all of a sudden I was making yards.

"On plays designed to get me outside, they had me stepping in to the guard. In New York, I always stepped in to the tackle, so I started doing it that way at the end of 1976. But that offseason, when they looked at all the films, nobody even noticed that.In some business people lose jobs for less. Now how would that make you feel?

"But I kept my mouth shut. I didn't want to cause any internal problems with the team. I'm not that way."

Now Riggins insists, all of that has changed. "Even if they want me to just block now, that's fine, although I don't think that's what they've got in mind for me," he said.

"The most important thing is that I'm excited about the things we're doing. The offense is going to be one of the best in the league. I believe that. If you're the blocking back for the 23rd best rushing team in the league, well, that's nothing to be proud of.

"But I'm not worried about that. Joe Walton (the Redskins' offensive coordinator) knows what I can do. They're going to use everyone to the fullest advantage. I think everybody can be a hero on Sunday, and everybody is going to get that chance That's what gets players enthusiastic. Everybody gets a shot at some glory.

"I never really set any goals. I kind of like to leave it unlimited. To say I'd like to get 1,000 yards, well that may not be enough. I'll carry the ball as much as they want to give it to me. I'd rather do that as much as anything."

He would also like to stay healthy. Riggins missed the final nine games of the 1977 season after sustaining ligament damage against Dallas.