The Minnesota Vikings must play the Dallas Cowboys for the NFC championship here Sunday without Francis Tarkenton. But if head coach Bud Grant can't have his most valuable quarterback, he still has a sense of humor.

On a day Grant definitely ruled Tarkenton out of action because of a slow-healing broken ankle, the Viking coach also seemed to plant his tongue firmly i n his cheek to take a small dig at the folks who run the National Football League.

"I'm not sure the league is happy with us being in the playoffs," Grant said via long distance telephone to a media gathering at the Cowboys' weekly press luncheon. "They'd rather have the glamour teams of the NFL."

Asked to explain, Grant said. "The league would just as soon have somebody else. I don't think we have that charisma they seem to like."

Told, "You sound just like George Allen," the Viking coach shot back, "You're right . . . but there's not a great deal of glamour that comes out of Minnesota. The image of the team doesn't come across like that."

Grant is one of the game's most subtle put-on artists, the same fellow who once complained about birds in the showers at a Super Bowl game, and had people believing he was upset. He wasn't.

And surely Grant had to be in a joyous mood today after his football team drowned the heavily favored Rams in the mud of the Los Angeles Coliseum.

The NFL office and the network television types no doubt would have preferred a Ram-Cowboy matchup, the better to light up all those Nielson boxes in populous southern California.

And surely the 14-7 victory caught a lot of folks by surprise, perhaps even the Vikings. They didn't send a scout to watch the Cowboys manhandle the Bears, 37-7.

Cowboy quarterback Roger Staubach also admitted he did not expect to be playing Minnesota for a trip to the Super Bowl. "They won a game no one though they'd win, except maybe the Vikings and their fans," Staubach said.

"I thought L.A. would win. But our coaches had studied both teams and they weren't that surprised. Playing the Vikings instead of the Rams is no advantage to us. They'll be on a real high. They've probably be as hungry as they can be to make up for their losses (four straight Super Bowl defeats.)"

hat was precisely what Grant was saying. Next to the Redskins, the Vikings field the oldest team in the NFL, with the starters averaging eight years of experience per man and the front four with a total of 53 years in the NFL.

Grant believes that is an advantage.

"The hungriest players on any team are the oldest players," Grant said. "That's who is means the most to. They have a better appreciation of what it's worth, not just moneywise, but what it does for you later.

"The players you may have trouble with are the younger players. They've come into an affluent game and most are making a lot more money than these veterans made when they first started. It takes a while to appreciate what it all means."

As Grant spoke, Cowboy coach Tom Landry calmly consumed his chopped steak and potatoes. Landry guides one of the NFL's youngest - and most devastating - football teams. Was Grant having a little more fun at the Cowboys' expense? Landry wouldn't say. "I agree with Bud," he said. "The older players understand the situations a little better and they know what it takes to win. A lot of the younger players also read the newspapers and get misconceptions (about how good they really are).

"As long as you've got young people on your team you never feel confident. But I feel comfortable with this team . . . we've got the capability of going to the Super Bowl, if they all play the way they're supposed to play."

That is precisely what occurred in Texas Stadium Monday. The Cowboys dominated the Bears in a rout that also came as a surprise to Staubach.

"I didn't expect what happened," he said. "A score like that or a game like that. It surprised me. Not that we won, but how we won."

The Cowboys prevailed primarily because they ran the football anytime they felt like it, came up with seven turnovers and sent Walter Payton back to Chicago in a small fog, his head throbbing from continuing punishment by Harvey Martin, Randy White and other Cowboy defenders.

Now all the signs seem to point to a repeat performance against Minnesota.

The Vikings, despite their new odd man defensive front, are vulnerable to the rush. The quarterback, veteran journeyman Bob Lee, obviously is not Tarkenton. And if the Cowboy flex defenses could strangle Payton what fate awaits the Viking's main offense threat, Chuck Foreman?

Even Landry had to admit "If we play the way we did yesterday, we'll be very tough."

Grant wasn't saying much. He'll bring his team to Dallas later this week - laughing all the way, no doubt. Vikings Were Prepared

Coach Bud Grant of the Minnesota Vikings had it on the word of Washington weather forecaster Gordon Barnes, well in advance, that it would come up rain in Los Angeles on NFC semifinal playoff day.

Sonny Jurgensen, Barnes' WTOP-TV-9 colleague, revealed on last night's Redskin Sidelines show that Grant had subscribed to Barnes' long-range weather service (a move considered on occassion by the Redskins, who did not follow through).

Not only did Barnes correctly predict the wet day in California, but when Grant asked where, he should prepare his team for the game conditions, the meteorologist advised: Tueson, Ariz.

The Vikings stopped over in Tueson en route to the Coast for three days of practice. It rained in Tueson.

And this week? A Viking spokesman said, "We won't decide until Wednesday where our practices will be held" for Sunday's NFC championship at Dallas.

Waiting for word from Barnes?