It is no grand calculation, this Washington Redskins' theory. The Redskins figure that Kansas City quarterback Bill Kenney will throw perhaps 40 passes today when they play the Chiefs at 1 p.m. before the standard sellout at RFK Stadium.

Quite simply, the Chiefs are the team with a new coach (former Dallas assistant John Mackovic) and without the ol' running game.

The Chiefs' running game, which operates out of the one-back set nearly half the time, seemingly tugs along a ball and chain. Running backs Billy Jackson (3.3-yard average) and Jewerl Thomas (2.3-yard average) have not been able to recreate the breakaway magic of former Chiefs running back Joe Delaney, who drowned in the offseason.

Consequently, the Chiefs (1-1) are averaging only 82.5 yards rushing per game. They have not gained more than 11 yards on any regular-season ground play. This is part of the reason the Redskins (1-1) are a seven-point favorite today (WRC-TV-4). Thus, you have this Redskins' theory.

It has kept the Washington pass rushers twitching in anticipation all week. "Still, unless they go berserk or weird," said Redskins defensive tackle Dave Butz, "they'll still run on first down. We just have to hold them under three yards on first down and make them go into a passing situation."

Butz laughed so slightly, perhaps reflecting on last Sunday's 23-13 victory over Philadelphia, when Eagles quarterback Ron Jaworski was sacked six times.

"This week's game," Redskins defensive end Dexter Manley said, "is left for our defensive line. I have to pressure their quarterback. What's his name again?"

Despite the nonrecognition, Kenney is a confident sort. Steve Fuller has been traded to Los Angeles. Former Penn State star Todd Blackledge is a reserve.

"I would have thrown it 40 times last week against San Diego if we had gotten the ball in the second half," said Kenney, who completed 22 of 30 for 188 yards in the game. In two games, Kenney has completed 42 of 62 passes for 435 yards and two touchdowns.

With Mackovic's pass-oriented offense comes bits of trickery; twice, the Chiefs have scored on passes thrown by someone other than the quarterback.

"The thing about this passing game," Kenney said, "is that, as I think San Francisco showed a couple years ago, you can throw a lot of short passes, then throw in a couple of big plays . . . If we could only establish the running game."

"Afraid? We're not afraid of a team that likes to pass. We look forward to it," said Redskins cornerback Vernon Dean, who again will be joined in the secondary by first-year strong safety Ken Coffey. Coffey will likely replace veteran Curtis Jordan, still suffering from a thigh bruise.

In the Kansas City glory years, it was the defense, with hardheads like Buck Buchanan and Curley Culp, that made certain that "Chiefs" was no misnomer.

How long ago were the Chiefs' glory years? Consider that they have had one winning season in nine years and haven't made the playoffs since the 1971 season (record during this duration of doldrums: 63-92-2).

The current Chiefs defense is led by ends Art Still and Mike Bell; the latter has two sacks so far. But the defense also has some newness and that has made for difficulty: linebackers Gary Spani (out until midseason) and Dave Klug (out for year) suffered knee injuries. The absence of veteran safety Gary Barbaro, another of agent Howard Slusher's unsigned holdouts, could have been too much to overcome if not for the competent play of replacement Deron Cherry.

Most crucially, the Chiefs' defense yielded 192 rushing yards to pass-crazed San Diego, in the Chargers' 17-14 victory Monday night.

The Chiefs' defensive goal today? Typically, Still said, "We have to stop (running back John) Riggins. We know he is a large proportion of their offense.

"What happened to us in the second half against San Diego," Still said, "was we tried the (standard) three-man rush, thinking they were going to pass. Then we tried to adjust, using a four-man rush. It caused problems for us."