Even if John Riggins shows up at Redskin Park this week, Coach Jack Pardee said yesterday, his role against the Dallas Cowboys in the season opener Sept. 8 "would be spot duty at best."

"A lot of whether he plays depends on the amount of working out he's done, and we just don't know that," Pardee said the day after his team's thumping of the Oakland Raiders at RFK.

"John knows our system, he knows what we're doing. But if he's not in shape, it would be hard to go with him at all. We also hope that by then (the Cowboy game) Wilbur Jackson will know what we're doing and play an important role."

No one in the Redskin organization knows what Riggins' plans are. As General Manager Bobby Beathard said yesterday, "I wouldn't be surprised if he came back, and I wouldn't be surprised if he didn't come back. But I haven't heard from him. I'm going to the office right now, maybe he'll be there."

He wasn't.

Pardee, of course, is breathing quite a bit easier because of Jackson. The coach said yesterday he would work his new fullback hard this week in practice and hopes to use him for as many as 30 plays in the Redskins' final exhibition Friday night at Tampa Bay.

"It's very likely that Wilbur will be playing a role in the Dallas game. I haven't seen him practice with our team. But he's played football long enough. He knows the basic plays.

"We used most of our regulars for about three quarters against the Raiders.

We wanted to see what kind of shape we're in, and I was pleased. The importantance of having Wilbur is that we can also keep Clarence Harmon fresh for what he does best, and that's going to help us."

Pardee also is looking forward to the arrival of holdout cornerback Jeris White to today's practice at Redskin Park, the first since the team broke training camp in Carlisle last week.

"We'll also have to wait to see how much we use him (against Dallas)", Pardee said. "We've been real pleased with our secondary, and we might not need to throw him in there. But Tony Peters (groin pull) got nicked a little against Oakland, so we just don't know. Tony's not hurt as badly as we thought he was, so we'll have to wait.

"But Jeris gives us depth with another good corner. He knows how to play.

He could work into our nickle defense system. We'll just have to play that by ear."

Pardee has several more major concerns this week, particularly with a cutdown from the current 60 to 50 players on Tuesday. "We've got some real tough decisions to make," Pardee said. "We're going to lose some guys who can play in this league."

One of Pardee's more perplexing problems is figuring out what's wrong with center Ted Fritsch, who had several awful snaps on punts against the Raiders. Mike Bragg had one punt blocked and another partially blocked.

"We've just got to get those snaps squared away," Pardee said. "I don't know what the problem is. He's had perfect snaps in practice. I just don't know how it's happening. I thought at first it was because he wasn't getting enough work at it, so we increased his work, I wish I knew."

Fritsch once was described by George Allen as the best snapper in the NFL and he is one of the team's most popular players. Is he now in danger of losing his job?

"I haven't made any kind of decision on the numbers," Pardee said. "I just don't know what we'll do right now."

Pardee was cheered yesterday by the prospect of having several of his regulars returning to practice. The Redskins played Oakland without starting linebacker Bard Dusek (hamstring), tackle Terry Hermeling (flu) and guard Jeff Williams (thigh contusion). Early in the game, Peters, defensive tackle Dave Butz (chest contusion) and linebacker Neal Olkewicz (sprained knee) went out.

Pardee said he hopes all those players will be able to work out this week, and added that he expects all to be available against the Cowboys.

"We made some mistakes at the start against Oakland, but after the first quarter, I was pleased with our offense and defense," Pardee said.

"We gave a lot of people a lot of work, and that's going to pay off in the long run. We didn't run the ball as well as I would have liked, but we also didn't have Hermeling and Williams in there. Right now though it looks like we've gto a lot of backup guys who can also do the job."

And if Riggins comes to Redskin Park this week, would that provide the sort of psychological lift the Redskins would love to have going into the the regular season?

"I thought we got that boost last week when we got Wilbur Jackson," Pardee said. "But if John comes in, he'll be welcomed by his teammates, there's no question about that. I'd like to see him here, too.