A Business School professor will give expert testimony this summer in a landmark lawsuit over the future of professional football.

Michael E. Porter, professor of business administration and a consultant to the National Football League (NFL), will provide testimony about the competition between the NFL and its four-year-old rival, the United States Football League (USFL), a source close to the case said yesterday.

The USFL, in a trial that began Monday, is seeking $1.3 billion for alleged antitrust violations.

Porter, one of several Business School professors who has led seminars for NFL executives in recent years, detailed strategies for combatting the USFL in a 1984 talk.

The USFL charges that Porter's seminar was one of many devices used by the NFL unfairly to thwart its fledgling rival.

The largest issue in the trial involves network television coverage. The USFL alleges that the NFL conspired with the three major networks to deny the USFL a TV contract this season.

The suit, filed in the New York Southern Division of the U.S. District Court, is expected to continue for six to eight weeks. Other witnesses could include sportscaster Howard Cosell, N.Y. Gov. Mario M. Cuomo and many football stars. Attorneys have not determined whether Porter will be asked to appear personally in addition to submitting a deposition.

Porter was commissioned by the NFL to discuss his specialty, business competition, at a meeting of 65 NFL representatives, including owners and general managers of the 28 teams.

"Porter was asked to give a speech about competitive behavior couched in terms of NFL and USFL," said Laura Steinberg, Porter's attorney. "In that talk Professor Porter had been asked what ways NFL could suppress the USFL."

Last fall, Porter testified by deposition that his discussion included "hypotheses" about issues like offering contracts to USFL and college players, and keeping the USFL from obtaining television contracts, Steinberg said.

Porter had also been retained by the NFL as a consultant, and he prepared a case study of the NFL-USFL rivalry for his students, said William Hokanson, spokesman for the Business School. He called it "more or less the private outside activity of Professor Porter."

Porter and NFL lawyers did not return repeated calls yesterday. A USFL attorney declined to comment.