George Allen is at it again. This time, Allen, the former Redskins coach and now owner-coach of the Chicago Blitz of the United States Football League, has signed a player with three years of college eligibility remaining. League Commissioner Chet Simmons almost immediately put the status of the contract in limbo.

The contract was signed in Chicago Tuesday by Willie Young, a 26-year-old lineman who quit the University of Illinois last week because he said he had to support his five children. Young, who is 6 feet 7 and weighs 280 pounds, was voted the Illini's most valuable defensive lineman by his teammates last season. He previously played service football.

Kay Schultz, a spokesman for the Blitz, had said yesterday that Simmons invalidated the contract. But the commissioner, reached at the league's New York headquarters, said, "The contract is under investigation now, and when I have everything in hand, I will make a decision. Maybe it will be in a couple of days. We don't want it to drag out any longer than necessary."

"This is like signing Herschel Walker (Georgia's all-America running back)," Illinois Coach Mike White said when he learned of the signing. He said that the Blitz had "raided" the Illinois roster for Young.

But an Illinois spokesman said yesterday that White was with Young last Friday when the player announced he was quitting the team because of financial problems.

"Young practiced for a week, then missed a week," the spokesman said. "Then he went to coach and said he'd decided to quit because he couldn't pay his bills and go to school."

"Young made it very clear that he wanted to play in the United States Football League and with the Chicago Blitz," Allen told the Associated Press. "He wanted to leave school to support his wife and family."

Young, a native of York, Ala., served in the Army for five years, starring on the team from Fort Bragg, N.C., before being recruited by White. He had been shifted to offensive tackle in spring practice and was running with the first team when he stopped working out. Friday, he publicly announced he was quitting and that's when the Blitz contacted him.

Neither Allen nor his son, Bruce, the team's general manager, could be reached yesterday.