The very thought is enough to scare the playoffs out of the Washington Redskins.

These are the frightening facts:

Fullback John Riggins has carried the football a total of three times the last two games. And still his lower back and hips are so painful he is expected to spend the weekend in traction at Sibley Hospital.

"Maybe John being in the hospital and being totally relaxed and in traction will really help him," Coach Joe Gibbs said yesterday. "They are having everybody check him over one more time for his benefit."

Riggins did not play in the 31-17 victory at Minnesota Thursday night. It was his second absence in a month; he also sat out the 28-14 victory over Detroit 20 days ago.

Observers assumed that, by playing so infrequently recently, the 35-year-old fullback with nearly 2,700 NFL carries was merely saving himself for the final two games, at Dallas on Dec. 9 and against St. Louis in RFK Stadium on Dec. 16.

After all, the Redskins are 9-5 with the victory over the Vikings that was crafted from a 31-0 halftime lead. They now hold a half-game lead over Dallas and the New York Giants, each 8-5.

"I'll try to play against Dallas," Riggins said Thursday night in Minnesota. "It will have to be something real major to stay out of it."

Yesterday, Gibbs insisted Riggins' absences against football proletarians such as Detroit, Buffalo (Riggins carried just three times, in the first quarter, of that game) and Minnesota were not planned.

"That's not the case," Gibbs said. "John was trying to go. I thought with a Thursday night game and being on national TV, I thought he'd get the juices going. Sometimes, he gets the juices flowing and his back stops hurting him. That's what he's told me."

But that didn't happen. Riggins was replaced by rookie Keith Griffin and veteran Joe Washington (56 yards), who combined for 108 yards and three fumbles.

Injuries to both Riggins and Washington this season have left the Redskins' running backs doing a do si do. Gibbs described it this way: "It started with Joe and John. Then it was just John. Then, it was Keith. Now, it's Keith and Joe." Got that?

In the visiting team's locker room at the Metrodome Thursday night, Riggins told reporters, "Yeah, it's getting frustrating. It's been a miserable year for me, physically.

"It started late in training camp. I felt it slightly against Miami (a 35-17 season-opening loss). It really started to pick up steam against San Francisco. It's getting to be a little ridiculous . . . It's gone on all season. It's finally gotten to the point where I'm concerned enough to go back into the hospital."

The problem is not entirely in the lower back of Riggins, who has rushed for 1,052 yards this season, already making this the third highest rushing total of his 13-year career.

Riggins said, "It could stem from the back. The real problem is the sides of the hips and spreading down. This week it went all the way to the back of my knees. It might be nerves. It might be muscles. It might be rheumatism. They've done all the tests. They were all negative and I still feel poorly.

"In the past, gradually the stiffness has gone away, I didn't have the same level of elasticity coming out of the locker room (Thursday). I didn't see any chance of playing the soreness out.

"The most discouraging thing is that I've been resting and still there is no improvement. I wouldn't go through another year like this, but that doesn't mean I'm announcing my retirement."

Riggins is in the final year of a two-year contract. The consensus at Redskin Park is that this likely will be his final season, though no one seems certain.

Three factors are always raised in support of the theory that Riggins will retire after this season: 1) the Redskins will owe him $2.6 million in annuities and deferred payments upon his retirement from the team; 2) his place seems assured in the league record books, and 3) his back has been in a continual state of pain all season. Why go one more, they ask?

General Manager Bobby Beathard said yesterday the Redskins' top priority in next year's draft is a running back. Beathard is smart enough to realize that, even if Riggins does return for one more season, he will be 36 years old and even Diesels run out of gas sometime.

"I think we have to make our plans as if John is not going to be there," Beathard said. "We'd be fooling ourselves if we did otherwise. If John says that he wants to play another year, that's no guarantee that he'll get physically better. He might be day to day a lot next year."

Of Riggins' possible retirement, Gibbs said: "I think the way this year ends will have a lot to do with it . . . I mean it will have to do with how far we go (in the playoffs) and how the whole thing works out for John. I think John's always had great timing. I've always felt that when John picks the time, it will be perfect."

Riggins has been the Redskins' finest postseason performer the team's last two Super Bowl seasons. He had rushed for more than 100 yards in the six previous postseason games, before he was limited to 64 yards on 26 carries in the 38-9 loss to the Los Angeles Raiders in the Super Bowl last January.

"He's practicing less and less and we keep hoping that he'll warm up and, all of the sudden, say, 'I feel pretty good.' That's what he did at New England (in the season's fourth week) and he took off (for 140 yards)," Gibbs said.

Gibbs said he was pleased with running back Washington's performance Thursday. "Him getting so many carries (16) is good for us. I thought he did well with the exception of the fumble," he said.

As for Griffin, who has fumbled seven times while carrying the ball just 105 times this season, Gibbs said, "Keith has proven he's a playmaker. I'm trying to say that you can't just put him on the bench because he fumbled."

Quarterback Joe Theismann has completed 45 of 57 passes for 534 yards in the victories over Buffalo and Minnesota. That computes to an astronomical 121.6 in the complex quarterback rating system.

Wide receiver Calvin Muhammad caught five passes Thursday for a career-high 115 yards, one a 68-yard touchdown pass. He has had 97 yards or more receiving in four of his seven games with the Redskins.

"Calvin has had great production," Gibbs said, noting that Muhammad will continue to start ahead of all-pro Charlie Brown, who recently returned from the injured list. Gibbs said Brown bruised a knee Thursday, but that the injury is not serious.

"I think Charlie, right now, is still getting in the groove," Gibbs said. "We'll play him more and more."

And what of the Redskins allowing Minnesota to score 17 points the second half to remain in contention until the final minutes? "There should be lessons learned from that," Gibbs said. "We turned the ball over, they made plays and we couldn't get it turned around." Dickerson Honored Associated Press

NEW YORK, Nov. 30 -- Eric Dickerson of the Los Angeles Rams, the NFL's leading rusher with 1,632 yards, today was named the player of the month by the Professional Football Writers of America.

Dickerson, who has a chance to surpass O.J. Simpson's single-season record of 2,003 yards, ran for 680 yards in November. He gained more than 100 yards in all four of the Rams' games during the month.