The Redskins probably are going to place fullback John Riggins on the injured reserve list today. Just the thought of it, coupled with concern over several key injured layers and a short week to prepare for the all-important Cardinal game put George Allen in a mood yesterday to match the weather outside - foul and stormy.

Allen had somewhat reluctantly agreed to hold a short day-after-game press conference, and when someone asked him about his plans at quarter-back for St. Louis, his voice turned angry and he began making a move for the door.

"I'm going to look at all the pictures right now," he said. "I've got to go to the phone to see about getting a player to replace Riggins. I'm not going to make any statements about anything that could be misinterpreted.

"I'm not going to make some statement where you guys (the media) can twist it around and trap me. No statements on the lineups, or any positions."

Does that mean Allen will shake up his comatose offense with another change of quarterbacks - from Joe Theismann to Billy Kilmer, the man who produced 24 points and three touchdowns against the Cardinals in the first meeting of the teams?

Allen wasn't saying, but other club sources indicate that Theismann should retain his starting position against a Cardinal team that ranks dead last in past defense in the NFC and has lost three starters in the secondary this season.

Those same sources also say Kilmer is healthy again after an early season pounding, and that Allen may turn to him if the offense doesn't move against the Cardinals in the first half Saturday.

The move on Riggins was not surprising because his injured knee had not come around as quickly as the club's medical men anticipated.

Allen had gambled Riggins might be able to come back for the Cardinal and Ram games, but "The doctor (team physician Stanford Lavine) told me Riggins probably shouldn't play . . . that the leg is such we shouldn't take a chance. I wish we'd known five or six weeks ago."

Allen also was fretting yesterday because both his defensive tackles - Bill Brundige (sprained foot) and Dave Butz (sprained ankle) - were hobbling. Brundige, in fact, was on crutches, and Allen called them both questionable for the Cardinal game.

"Nah," said Brundige. "I'll be all right. It has to be for this game. It just means I might miss a few practices."

With Brundige and Butz ailing, the Redskins will be reduced to four relatively healthy defensive linemen, a figure that includes reserve Dallas Hickman, who has a broken hand.

So Allen may try to scrounge up an unemployed defensive tackle or end unless, of course, he is more concerned about the wide receiver position, another problem area.

Frank Grant and Larry Jones suffered knee bruises agains the Buffalo Bills and were limping yesterday. Trainer Bubba Tyer said both should be ready for the Cardinals, and a healthy Charley Taylor also is available if either man is not.

Allen also indicated linebacker Chris Hanburger is still not ready to play an entire game. Hanburger has done that only once this season - against the Cardinals in the first encounter - and Allen said "his leg (knee) is unstable. He's questionable."

Despite the loss of Hanburger, Dennis Johnson and Pat Fischer this season, the performance of the Redskin defense, Allen said yesterday, "has been as good or better than any we've had in seven years here. But they have to do it again this week. If they don't, all the other hard work and hitting and effort is down the drain."

The Redskins will face a Cardinal team that is having offensive problems, scoring only 21 points in the last two weeks in humiliating losses to the Miami Dolphins (55-14) and N.Y. Giants (27-7).

"We're not playing very well and this is not the time of year for it," said Joe Sullivan, the Cardinals director of operations. "You can't win with 10 1/2 points a game, I know that, and George has got that defense playing great football.

"Yes. I did say that they would have problems with Chris out of there. But you really have to hand it to George. He does such a complete, thorough job preparing that team, down to the very last detail. And they've done a lot more than anyone expected.

"If he gets that team into the playoffs, I'd vote for him as the coach of the year. He started out the season with injuries that should have put this team out. But they never folded after they lost a couple of key games, and that's one thing George does so well.He gets them to come back and he deserves a lot of credit."

The Cardinals also recovered smartly after losing three of their first four games, but Sullivan admitted yesterday, "I really don't know what to make of our team. We had great practices all last week, and then we go out and lose to the Giants.

"I know this, the Redskins will be ready to play a football game against us. We know we're in for a hell of a game. That never changes."