They may have been members of the National Football Conference East all-star team, but that didn't matter to the George Washington University soccer players. It was raining very hard, it was their practice field and they wanted to get under way.

That was all right with fullback John Riggins, whose enthusiasm for the workout ended with the first touch of moisture.

"You might as well go home," he yelled to the soccer players. "We are going to be out here the rest of the afternoon."

Even Chris Hanburger, the NFC coach in this NFL Players Association all-star game, had to laugh. But he still continued practice for another 10 minutes before mercifully ending things.

This was Day 1 of workouts for Sunday's game in RFK Stadium. Fortunately for both teams, they have three more days to bring in reinforcements. Otherwise, fans may have to settle for a touch football game.

The NFC had only two defensive linemen among 29 players. The AFC East, which practiced in the morning with 30 players, had three defensive linemen but only one quarterback, New England's Steve Grogan. The NFC could muster just 10 defensive players and a mere five offensive linemen.

"They promised us reinforcements by Thursday," said AFC Coach Tom Matte, who conducted his session with an appropriate touch of mischief. At one point, he looked around and asked if anyone wanted a break, knowing full well hardly any substitutes were available. A lot of hands shot up.

"We have more players coming in," said the NFLPA's Brig Owens, who is coordinating the games. "Wesley Walker (of the Jets) called and said he was bringing four players with him. We will have enough by the time we play."

Walker did arrive late in the afternoon, along with fellow Jets Marion Barber and Bruce Harper, both running backs, and two Buffalo Bills: defensive lineman Mark Roopenian and defensive end Ken Johnson. Those additions just about fill out the AFC roster, which still lacks a quarterback. The NFC added Terdell Middleton of Tampa Bay.

One of the ironies of this game is that many players don't think it will ever take place. They believe a settlement in contract negotiations with the league will come before Sunday's 4 p.m. kickoff.

"This is fun, because you get to meet a lot of these guys for the first time," said Buffalo's Jim Haslett. "But I hope we never play this game. That would mean there is a settlement and we can get back to playing for our own team."

"I'm doing extra running after practice," said Washington's Clarence Harmon, "because I just have a feeling things will be over by this weekend and I want to make sure I'm in shape."

The game apparently won't be stopped as a result of any legal action by the NFL. A U.S. Court of Appeals here yesterday scheduled oral arguments next Wednesday on whether the league must bring suit in Washington to prevent players from particiapting in these contests. The NFL, hoping for a ruling this week, had asked the appellate court to nullify a ruling by U.S. District Judge John Penn last week that barred the teams from filing suit in state and local courts to halt the players.

Harmon was one of seven Redskins practicing with the NFC. The others were Joe Jacoby, Charlie Brown, Jeff Bostic, Tony Peters, Riggins and Rick Walker, who was added to the roster yesterday. Guard Mark May is ill and may not play. Bostic, normally a center, moved to guard. The other guard was his brother Joe, of the St. Louis Cardinals.

Of all the players who have shown up, the quarterbacks probably are having the most fun. The AFC passing offense was designed by quarterbacks Bob Avellini and Gary Danielson Tuesday night while they were watching the World Series. Running plays were borrowed, according to Danielson, from the pre-Redskin offense. The NFC offense has been tailored to suit Grogan, who has been in the midst of quarterback controversies during most of his pro career.

"This might be one of the best situations I've been in," Grogan said with a smile. "No matter what I do, they can't jerk me."

Riggins, easily the highest-paid player in the game, brought along his family to practice. At one point, son Krafton shadowed him through every step of mock running drills. Later, Krafton posed for photographs.

"Geez, don't mug for them already," Riggins said, laughing.

The workouts started and ended in confusion. No one had a key to let the players into the practice facility near RFK. In the afternoon, Hanburger told his charges to report to the stadium today at the same time the AFC was supposed to practice. Informed of his mistake, Hanburger announced he was checking with the union to see who was wrong.

"Tell them that if we can't practice in the afternoon, we'll go on strike," said Louie Giammona of the Eagles.