Chicago Blitz Coach George Allen said yesterday he was only joking when he told a reporter from the Chicago Tribune Thursday that he offered Georgia's Herschel Walker $9 million to play for his team in the new U.S. Football League.

A Florida newspaper had reported that "close friends" of Walker's family said Allen offered the all-America, who still has a year of eligibility left at Georgia, $1 million to sign with the Blitz. When Allen was asked about the report, he said, "It's wrong. I didn't offer $1 million. It was $9 million," the Tribune reported . . .

The 57-day NFL players' strike cost the New York Giants more than $6.2 million in anticipated revenue, team officials said. However, the club saved an estimated $2.3 million in salaries, according to Raymond J. Walsh, team vice president and secretary.

The team lost about $3.8 million in television revenue, $1.2 million in ticket sales, $75,000 in concession revenue and $200,000 in radio revenue, Walsh said . . .

Brian Sipe, the NFL's most valuable player in 1980, will be replaced by backup quarterback Paul McDonald Sunday, Cleveland Browns Coach Sam Rutigliano said. "Brian Sipe hasn't played to his level the last four games," said Rutigliano, whose team has lost three straight games and fallen to 2-4.