The Michigan Panthers of the United States Football League have offered Washington Redskins fullback John Riggins a two-year contract worth more than $1 million, according to USFL sources.

Riggins, who led the Redskins to a Super Bowl victory over the Miami Dolphins with a record 166 yards rushing, earned $330,000 last year in the final year of his contract. He is now a free agent.

Redskins owner Jack Kent Cooke said today, "I have no idea what they (the Panthers) are doing. I very definitely will meet with him (Riggins) soon and I fully expect to sign him."

Alfred Taubman, the Panthers' principal owner, is one of the new league's wealthiest owners, having made a fortune in the development of shopping centers. Neither Taubman nor Riggins was available for comment today, but Judge Peter Spivak, the Michigan team's president, said of the Riggins offer: "If it's true, I don't know anything about it."

Bobby Beathard, the Redskins general manager, said on Friday he has not yet met with Riggins to discuss a new contract but expected to meet with him within the next two weeks. He also was not available today.

The question remains whether Riggins is using his negotiations with the Panthers as leverage to raise significantly his salary with the Redskins. League sources, however, describe the talks as serious.

The day after the Super Bowl, Cooke said he would "use every power of persuasion . . . to keep him on the Redskins . . . John Riggins is as endemic in our organization as the name Redskins."

Although the league's complicated territorial system dictates that the Boston Breakers have rights to Riggins because he attended Kansas, sources said that Michigan is seeking or has already acquired those rights from Boston.

Federals President Jim Gould said that he and Berl Bernhard, the team owner, had discussed the possibility of pursuing Riggins but had rejected the idea, not only for financial reasons but for "good faith" reasons as well.

"We felt we didn't want to be responsible for taking Riggins," said Gould. "We are not going to initiate any moves to get John Riggins. We don't want to jeapordize whatever relationship we have with the Redskins and their fans. We want those fans to be our fans, too."

Gould said the only way the Federals would approach Riggins is if it became clear that he was ready to leave the Redskins and the city. "If that were the case, it might be a different story, because he would be in danger of leaving Washington altogether," said Gould.

From both an athletic and marketing standpoint, the USFL franchises have found it important to have one or two veteran or college stars on their rosters. The Federals, for example, signed running back Craig James to a four-year guaranteed pact worth approximately $2 million.

Michigan's only "big-name" player is David Greenwood, a defensive back from Wisconsin. The Panthers are still holding talks with representatives of Michigan receiver Anthony Carter. His agent, Boston attorney Bob Woolf, said today that Carter likely will sign a four-year contract reportedly worth $1.25 million with the club on Monday.

The owners of the USFL teams have an unwritten agreement that they all spend $1.5 million per year on salaries for 38 of the 40 players on their rosters. They do, however, have a "sky's the limit" understanding for the remaining two spots.

While Riggins has officially been declared a free agent, it is clear that the USFL is also searching for players elsewhere.

Cris Collinsworth, an outstanding wide receiver with the Cincinnati Bengals, still has two more years left on his contract, but he has reportedly had discussions with Tampa Bay Bandits owner John F. Bassett.

The two parties have discussed a contract that would make Collinsworth a very wealthy man after his agreement with the Bengals expires in 1985. Sources close to the Bandits say the four-year package could exceed $3 million including bonuses for signing and reporting to camp.

These reports come after a week of controversy surrounding Heisman Trophy winner Herschel Walker of Georgia. According to a story in the Boston Globe, Walker signed a contract with the New Jersey Generals worth as much as $16.5 million over six years. Other USFL sources put the offer at a $10.5 million over eight years.

Both Walker and Generals owner J. Walter Duncan, a Norman, Okla., oil man, acknowledged that they met but denied any contractual agreements. Walker, for his part, says he wants to play at Georgia for his senior year.

"I did not sign a contract," Walker was quoted as saying in Sunday's Atlanta Constitution. "I haven't seen a contract, and I don't expect to see one until next year when my eligibility is up."

While a number of celebrated college athletes have signed lucrative contracts with USFL clubs, many have decided to wait for the NFL draft. Pittsburgh quarterback Dan Marino, the USFL's first draft choice overall, turned down the Los Angeles Express' reported offer of $2.2 for four years.