The Dallas Cowboys denied published reports that the National Football League team is for sale for $40 million.

Tex Schramm, the Cowboys' president and general manager, said the report in Sunday's Boston Globe was false. He also pointed out that Texas Stadium, which according to the story was to be part of the sale, is owned by the City of Irving and is the home field of Southern Methodist University. The Globe said a report had been confirmed that Clint Murchison Jr., citing failing health, wants to sell the NFL club he has owned since it began in 1960 . . .

Cincinnati Bengals wide receiver Cris Collinsworth describes as "greatly exaggerated" reports that he is considering an offer to do promotional work and eventually play for the United States Football League.

"I would not do anything that would jeopardize what I have in Cincinnati . . . The rumors are greatly exaggerated," he said . . .

Bob Ledbetter, who left the coaching staff of the New York Jets after head coach Walt Michaels resigned last week, has joined the New York Giants as offensive backfield coach. Ledbetter will replace Bob Lord, the Giants' backfield coach since 1979, who resigned, Giants spokesman Ed Croke said. No reasons were given for Lord's resignation . . .

Chuck Foreman, 32, a five-time Pro Bowl player with the Minnesota Vikings who last month ended two years' retirement to join the new United States Football League, was released by the Los Angeles Express.