Anthony Carter, an all-America wide receiver from Michigan, signed a reported $2 million, four-year contract yesterday with the U.S. Football League's Michigan Panthers, one day after sources said the team offered running back John Riggins of the Washington Redskins a $2.5 million contract for three years.

Carter's signing was the second major acquisition of the week by a USFL team. On Wednesday, the New Jersey Generals signed Herschel Walker of Georgia to a $5 million, three-year contract.

At a news conference yesterday in Bloomfield Hills, Mich., Carter said he signed with the USFL rather than wait for the National Football League's April draft mainly because he wanted to remain in Michigan.

"I don't have any regrets. People here have been real good to me," Carter said. "The Panthers also impressed me. They gave me all the time I needed to sign."

Carter, a 5-foot-11, 160-pounder, was a three-time all-America. He set an NCAA record by averaging 17 yards every time he caught a pass or a kick, and averaged a touchdown for every four catches. Jim Spavital, general manager of the Panthers, said Carter will not begin practicing with the team until midweek.

Riggins, who received the Panthers' offer on Friday, was back in Kansas yesterday. He was honored during halftime ceremonies at a basketball game at the University of Kansas, his alma mater, according to Richard Berthelsen, staff counsel of the NFL Players Association. Berthelsen was present during Riggins' negotiations with the Panthers.

Redskins General Manager Bobby Beathard said he would meet on Tuesday with Riggins, who was named most valuable player in last month's Super Bowl. Beathard said he did not know if the Redskins would be willing to meet the offer reportedly made by the Panthers.