The United States Football League's $1.32 billion antitrust lawsuit against the National Football League -- a legal rendition of Herschel Walker running at Refrigerator Perry's midsection -- will begin with selection of jurors Monday in a Manhattan courtroom.

Judge Peter K. Leisure, of the U.S. District Court for the Southern District of New York, will preside as the USFL attempts to prove that the NFL violated Sections 1 and 2 of the Sherman Antitrust Act by illegally "tying up" the three television networks. USFL attorneys assert that this effectively prevented the USFL from gaining the revenue and exposure necessary to compete.

Besides damages, the USFL is seeking injunctive relief in the form of forcing the NFL off at least one network so that the USFL might negotiate a deal of its own with that network. Since deciding to move from the spring to a fall season in 1986, the USFL has been unable to secure a network contract.

Above all, the trial will provide a detailed examination of how the television dollar fuels and drives the professional football industry.

The trial is expected to last between six and 10 weeks. The final decision could alter drastically the current shape of professional football, Big Bang style with a complete USFL victory, or it could serve merely to reaffirm the strength and staying power of the NFL empire, running strong after 66 years, and to strike dead the USFL, a mere pup of three years.

Stephen Ross, managing partner of the Baltimore Stars of the USFL, said if his league loses all points of the suit, "We'd have problems. I don't know if it's the end of the league, but, well, I just don't have an answer to that."

The USFL commissioner, Harry Usher, said the league will play this fall regardless of the outcome of the lawsuit. However, Usher said that if the USFL loses all points of the suit and cannot secure a network contract, "I wouldn't be critical of the owners if they decided to cash it in" after this season.

Commissioner Pete Rozelle of the NFL has termed the suit "baseless" and one NFL owner privately said the suit "is made of whole cloth; it's preposterous." Yet, the establishment league has been concerned enough to hire three law firms to defend it. Most recently, the league hired Frank Rothman, a California-based attorney who returned to private law recently after having served for four years as chief executive officer of MGM/UA Entertainment.

Dallas Cowboys President Tex Schramm said, "I happen to feel confident we will prevail, but whenever you go to court, it's like anytime you go to a football field -- anything can happen."

NFL owners continue to say they will not accept any form of merger with the USFL. Usher said of a possible pretrial settlement that would include a merger, "Anything is possible, but I'm certainly not anticipating it. We are gearing up for a substantial trial."

Tangled amid thousands of as yet unanswered questions, there exist several possible results. Most notably:

*The NFL could win on all points and this most likely would represent the end of the USFL in the near future. If the USFL disbands, running back Walker would become available to join the Dallas Cowboys, running back Kelvin Bryant would be able to join the Redskins, quarterback Jim Kelly (or at least his NFL playing rights) would head to Buffalo and other USFL players and coaches would become eligible to try to break into the NFL.

*A USFL victory on all points could put the NFL in severe financial disrepair and could allow for a complete breakthrough for the USFL in every respect. The NFL already has lost an antitrust case to Al Davis and his Los Angeles Raiders that, barring a reversal in the league's current appeal, eventually could cost the 27 other NFL owners $70 million in damages.

There also has been speculation that, if the USFL wins on all points, the NFL might agree to bargain for some form of merger, accepting as many as four USFL teams. NFL owners say that's mere gossip spread by the USFL.

"If we win," said Donald Trump, owner of the New Jersey Generals of the USFL, "we get a lot of things. We get whatever we want."

One source close to the USFL said that in order for that league to continue with a legitimate hope to challenge the NFL in the near future, it must win both the injunctive relief (forcing the NFL to give up at least one network and then being able to strike a favorable deal) and a substantial damage award. Without a substantial damage award and a substantial network television contract, the source said, the USFL would be hard-pressed to compete with the NFL in most every respect, including signing marquee players.

"And just because a judge orders the NFL to give up one network," said a television executive, "no one can force that network to work out a contract with the USFL."

The USFL's Usher, who said he expects any damage award to be held up by legal appeals, remains outwardly optimistic that a deal could be struck with a network that is disengaged from the NFL. He said, "There's no reason why a network would simply not talk to us unless they are already carrying the NFL and are looking to stay in the rotation for the Super Bowl . . . That's not the American way."

The USFL will be represented by litigator Harvey Myerson, a partner in the New York firm of Finley, Kumble, Wagner, Heine, Under-berg, Manley, Myerson & Casey. Last October, Fortune magazine identified Myerson as one of the nation's top five specialists in corporate calamity, noting that Myerson "has built a reputation for pulling companies out of deep trouble."

Myerson said that sportscaster Howard Cosell, Sen. Alfonse D'Amato (R-N.Y.) and Davis, the NFL Raiders' managing general partner, will testify on behalf of the USFL.

Of Davis, Myerson said, "He'll give very important testimony regarding a number of things the NFL does in regard to the USFL which we would otherwise not have had without an NFL owner." (Davis and the Raiders are not named as defendants in the USFL suit.)

The USFL is asking for a $440 million damage claim that, under antitrust laws, is tripled, creating the $1.32 billion figure. The damage estimate is based on projections (plus cost of living increases) from the network contracts of the American Football League in the 1960s before that league merged with the NFL.

The damage claim assumes that the USFL, which has played only in the spring thus far, would have competed in the fall over the previous three seasons. The NFL has protested this claim, pointing out that the USFL began as a spring league with TV contracts from ABC and a cable network.

In pretrial arguments, NFL attorneys asserted that the USFL's problems were self-inflicted and that the real motive behind the suit is to force a merger. The USFL, in trying to prove that the NFL had an anticompetitive intent, is expected to cite a memorandum written by Jay Moyer, an NFL attorney, in 1973 that suggested that one reason for the league to renew ABC's Monday Night Football contract was that "an open network may well be an open invitation for the formation of a new league."

Cleveland Browns owner Art Modell, who has been a member of the NFL's television committee for many years, said the USFL "will have a hard time proving that anything happened between the NFL and the networks behind closed doors, because nothing ever did. No crosses were brought to bear on the networks. They can stay in court for 100 years trying to prove it and they never will. Nothing ever happened."

Modell said the NFL has no exclusivity clauses with the networks and the USFL is free to negotiate with the networks now. He said, "They are free to get ABC to televise their games on Sundays. They can get NBC or CBS to televise their games on Monday nights . . . We haven't done anything to inhibit that league's progress."