The National Football League yesterday turned down former Texas Christian University running back Kenneth Davis' appeal for permission to turn pro immediately and filed suit in Texas State Court asking that its so-called "Red Grange Rule" be upheld.

Under the rule, players who have begun their college season are prohibited from playing in the NFL the same season. Davis played the first game on TCU's 1985 schedule before he and six other players were suspended from the team for accepting payments from boosters. Davis and his agent, Mike Trope, met for 75 minutes with NFL Commissioner Pete Rozelle Tuesday, seeking a supplemental draft that would allow him to play in the NFL this season.

The NFL said that permitting Davis to turn pro immediately could result in players "with or without encouragement from agents" leaving school prematurely to seek pro careers. A league spokesman said the NFL suit had been filed in Fort Worth.

"Given the threat of legal action by the agent for TCU's Kenneth Davis, we have authorized our attorneys to seek a court ruling in Davis' home state that this long-standing league rule is reasonable," the NFL said in a statement.

" . . . Speaking practically, an exception made here would likely produce an unmanageable situation in which players engineered their departures from college during the season, disrupting both the NFL's competitive balance and their college programs as well. We are not prepared to open that door."

"We're not seeking any injunction. We're not looking for any monies," Joe Browne, the NFL's director of information, said. "We're just asking the court to make a declaratory judgment." . . .

Joe Cribbs, the Buffalo Bills' premier running back in the early 1980s, signed a contract to return to the NFL team after a two-year stint with Birmingham of the U.S. Football League. The terms of the deal were not announced, but Cribbs reportedly will be getting $2 million for four years plus a $500,000 signing bonus.

Coach Hank Bullough said Cribbs won't be playing against the Patriots in Foxboro, Mass., on Sunday, "but he will be in shape to play the following weekend."

Cribbs' agent, Louis Burrell, said Thursday night a deal had been reached, except for some "small, minor points." Cribbs had to buy out the final three years of his Birmingham contract, according to his agent. But Burrell said that Buffalo-area banker Robert Mayer arranged a loan for Cribbs to complete the buyout.