Chances, that the Redskins will trade for a fullback this week are "slim," General Manager Bobby Beathard said today.

The redskins have had feelers out since John Riggins quit camp July 27. Riggins is demanding that the 1981 option year of his salary contract be guaranteed and that his salary be raised from 330,000 to 500,000, informed sources have said.

Otherwise, the nine-year NFL vetran will retire, he says.

The Redskins have found that fullbacks are not plentiful this summer. If he trades, Beathard says "the sooner the better; we want him in here to learn the system."

One NFL personnel man said today, "It seems like people are looking for a fullback; I haven't heard fullbacks offered around. A lot of teams play with small fullbacks because the 230-pound ones are rare."

Beathard has called around the league and sent scouts to every exhibition last weekend. The personnel men met here tonight to evaluate what they had seen.

"Some teams want to go another one or two games to see what the young guys are going to do, so it's a waiting game now," Beathard said.

That the Redskins do not want just any fullback and reaffirmed today when Beathard again was asked if he was interested in Larry Csonka, the big fullback cut last week by Miami after a salary dispute.

"No way," Beathard replied. "In fact, Ed Keating (Csonka's agent) has been calling me. I don't think he can make this team."

If the Redskins do acquire another fullback, he probably would back up Clarence Harmon. Harmon, had Riggins not walked out, would have been contesting Buddy Hardeman for the starting halfback job.

Since Redskin running backs gained 204 yards and averaged 5.1 yards per rush in their 13-3 exhibition-opening victory over the Colts, some club officials believe they cannot improve the team by trading now.

One of them notes that Don Testerman, a big fullback who received the game ball against the Colts, would be a risky proposition as a starter. But the same person feels very comfortable with him as a backup.

The major drawback with Testerman is that he is slow.

"If they are limited in one particular phase, you don't ask them to do it," said Fred O'Connor, who coaches the running backs. "Testy is an inside power runner, a good blocker and an adequate pass receiver."

Testerman, a 230-pounder fourth-year player from Clemson, came in trade from Seattle following the 1978 season. He was on injured reserve all of the next season. But in two scrimmages and the first exhibition, he has impressed this year's opposition.

"I don't want to see him again soon," said Ernie Accorsi, the Colts' assistant general manager. "The way Testerman ran against us, he looks Like Jim Brown."

Beathard, who before that game said he would call Riggins early this week, was happy enough with his running backs' performance against Baltimore to decide not to make that call "right now," as he put it Tuesday.

The general manager, who hopes Riggins returns, is adamant that the Redskins will not renegotiate. He also said that trading Riggins would be "a last resort." Another team would have to meet the Redskins' price before they allowed that team to talk to Riggins and reach terms with him.

Beathard said the Redskins have not yet set a price on Riggins.

Of his other dissatisfied player, Beathard said that he doubts the Redskins would be able to trade Jeris White, the cornerback they obtained from Tampa Bay on draft day but who never reported. White also wants to renegotiate his contract.

Beathard based his statement, he said, on the terms being asked by White's agent, Howard Slusher.

Slusher also represents Sam Cunningham, a big fullback the New England Patriots might be willing to give up. But it is unlikely that, after what has happened with White, Beathard would deal with Slusher on another player. h

The experiment to make a punt returner of linebacker Monte Coleman has ended. "I missed those (two) interceptions Saturday," Coleman said. "They took me off punt drills and got me on another interception drill. It seemed like a good idea. I would do it if they wanted me to, but it's not logical. They've got a good punt return man now -- Mike Nelms." John Hilton, special teams coach, said: "Now that Monte's playing a lot, it would be difficult. The way Nelms catches the ball, he'll be a tough one" . . . Cornerback Joe Lavender was released from Carlisle Hospital this morning and is expected to practice Thursday, Coach Jack Pardee said. Lavender reportedly has intestinal flu, but Donald Knowland, the team's internist, said Lavender might have food poisoning from fish he and a friend ate in Philadelphia. The friend also became sick, Knowland said.

Three free agents were cut today: safety Mark Freeman, punter Allen White and running back Sam Thomas. Pardee said Freeman and White had asked for an early decision on their fate because they were seeing little action in practice. "So why waste their time?" Pardee said. The cuts reduce the roster to 73, including Riggins and White. The club must be down to 60 Tuesday afternoon . . . Best plays of the two practices: a one-handed catch in the open field by Hardman and an interception and "touchdown" by Coleman . . . Today's visitors included representatives of the 101 stations that give the Redskins the largest radio network in the NFL. Also here was Robert Mitchell, son of the team's executive assistant to the president. Mitchell, a standout running back at Sidewell Friends, will leave Saturday for his sophmore year at Stanford. He has been moved back to running back from defensive back, where he played as a freshman. He majors in English and History and is looking forward to law school.