"It's not life or death," said the quarterback, Joe Theismann, "but it's darn close."

"All the talking is finished, nobody has to make speeches or say anything at all because we know what's at stake," said the middle linebacker, Haorld McLinton.

"We've got to win, we just have to," said the coach, George Allen.

And, so as the green machine known as the Philadelphia Eagles comes to town for a 1 p.m. game today at RFK Stadium (WTOP-TV-9), all of the Washington Redskins know their football season is clearly on the line.

The oddmakers know it too, because they have installed the desperate Redskins as a 5 1/2-point favorite.

The Redskins, now 3-3 and three games behind the undefeated Dallas Cowboys in the NFC East race, now are playing for a wild-card berth, and another loss at this stage halfway through the season would be almost fatal.

Allen gave his team a rare day off from practice yesterday, a move designed to lift spirits and give aching bodies another day to heal. He also was hedging on lineup changes, though it appears the team's Great Offensive Shakeup is upon us.

Allen is hoping Theismann will the biggest shaker of all, that he will be able to hype a feeble offense that has produce only eight touch-downs in six games. Though neither coach nor quaterback would say for sure yesterday that Billy Kilmer has been benched for the game against the 2-4 Eagles, Theismann sounded very much like a starting quaterback.

"I feel confident I can get the job done," he said. "I don't think I'd be here if the coach didn't believe in me. It's a total pressure situation, but if you don't like the heat in the kitchen, you can always move to another room in the house. I don't plan on moving."

A year ago, Allen turned to Theismann in the fifth game of the season when Kilmer was hurt against these same Eagles. In his first start, Theismann completed 20 to 37 passes for 270 yards and two touchdowns in a valiant but losing cause against the Kansas City Chiefs.

He started five games in all last year and won three - before a foolish interception and a painful hip pointer, both inflicted by the New York Giants, drove Allen back to Kilmer for the stretch drive.

Now Theismann has another chance to establish himself as the Redskins No. 1 quaterback. "I can't think about that," he said. "I've just got to go out and play football. It's imperative that we win. You just can't go out and say, 'Well, it's only my first game,' or 'I've been sitting on the bench all season.' There are no excuses.

"I have to be as ready as any starter in the NFL to play a football game on Sunday. The guys have to believe in me and I have to believe in them or it won't work. I know this is probably as important a game as we've had in seven years since George came here."

No Allen Redskin team has ever lost three straight football games. And no Allen team has been more decimated by injuries this early in the season, though the coach insisted yesterday, "It's not our style to use injuries as a crutch."

On offense, Theismann will replace Kilmer at quaterback. Calvin Hill probably will open at tailback for Mike Thomas; Clarence Harmon will start at fullback for injured John Riggins, and Danny Buggs will start in place of another injured player, Charley Taylor at wide receiver.

Defensively, Mike Curtis will replace Chris Hanburger at right linebacker, Gerard Williams opens at Pat Fischer's left corner and Eddie Brown will probably take over for Jake Scott at free safety.

Allen said he still held out some hope that Scott could play, depending on how his pulled leg muscle responds in pregame warm-ups. Defensive tackle Diron Talbert (hip pointer) and Bill Brundige (bruised knee) also are maybes, though both should be available against an Eagle team with its own physical problems.

Philadelphia's largest worry is the health of quaterback Ron Jaworski, who suffered a fractured right thumb and slight concussion last week in a touch 16-10 loss to the Cowboys.

Jaworski, the so-called Polish rifle, hardly resembles Annie Oakley for bulls-eye accuracy with 48 per cent completion rate and 12 interceptions. Former Allen assistant Dick Vermeil, the Eagle head coach, says he will start Jaworski, who has also thrown nine touchdown passes in six games. Allen, of course, is properly wary.

"He's a bober," Allen said. "He's got that fast ball and he can bomb you. A lot of their plays have been big plays and they beat the daylights out of the Giants. New York was hardly even in the ball game."

Theismann, meanwhile, is far more conscious of a Philadelphia defense that has yielded only 87 points while belting opposing quaterbacks 19 times to equal last year's entire team total of sacks.

The way the Redskins offensive line has been pass blocking lately - Redskin quarterbacks already have been dumped 22 times - Theismann will be expected to use the rollout, sprintout and waggle-moving pocket-type passes well suited to his mobile, move-around style.

Theismann also surely will notice the presence of a rookie cornerback, Herman Edwards, in the Eagle lineup. Nevertheless, the Eagles use three down lineman and four linebackers, an alignment that puts a whole bunch of people into the pass coverage for extra help.

With former Maryland man Larry Marshall among the league leaders returning punts and kickoffs, the Eagles have rather formidable special teams. Still, Horst Muhlmann has tried only four field goals and also kicks a low ball, susceptible to being bocked.

But Allen didn't seem all that preoccupied with the state of the Eagles yesterday as he was concerning the mental frame of mind of his own struggling football team.

"I just wish I could make them feel the way I feel right now," Allen said.

"If I could, we'd probably win the game. Physically, they are ready, but the mental part is the most difficult."