Commissioner Harry Usher of the U.S. Football League said yesterday he would not criticize "courageous and valiant" league owners if they chose to fold the USFL after the 1986 fall season should they lose their upcoming $1.32 billion antitrust suit against the National Football League and fail to secure a network contract.

"If we lost the lawsuit and didn't have the network contract, I wouldn't be critical of the owners if they decided to cash it in," Usher said. "Goliath keeps marching at us and devises plans to injure the USFL. I was never in on the AFL American Football League , but my guess is every year with a struggling league you go through speculation with the press wondering, 'Are you going to be around year after year?' "

Usher stressed that neither he nor the eight league owners believe the USFL will lose the trial, which begins Monday in the U.S. District Court for the Southern District of New York. He said the owners haven't discussed what would happen should the USFL lose the suit.

"The only question," Usher said from his Los Angeles home, "is, 'How big are we going to win?' "

Usher said the USFL will play a fall schedule this year, regardless of the outcome of the trial. "But at some point you run out of dollars," he said. Usher estimated that USFL owners have lost "in excess of $150 million" since the league began in the spring of 1983.

ABC televised USFL games over the past three years when the league played in the spring. However, the USFL has been unable to secure a network contract since moving to a fall schedule. In its suit, the USFL enjoins the NFL from appearing on all three networks and demands that the NFL's contract with at least one network be voided.

"I think an amazingly courageous and valiant run has been made by USFL owners, putting in their money and fighting Goliath," Usher said. "It's tough being David. It makes for a great myth, with the slingshot, but it's tough in the real world.

" . . . I don't think many people expected the USFL to conduct its fourth annual draft as it did this week . . . It would be tragic if the USFL folded because I believe it is unhealthy to perpetuate this lock the NFL has on the media and the networks and to end up with that same lock not even being dented."

Usher said he would not speculate about what course the USFL would take if it loses on all points of the suit. "What will happen beyond 1986 is up to the owners," Usher said. "[But] there has been tremendous damage [inflicted by the NFL] and to ignore it would be unfair."