Steve Young, the $40 million quarterback who is thinking about taking his talents to the National Football League, said he has received no assurances from U.S. Football League Commissioner Harry Usher that the foundering Los Angeles Express franchise will be more stable in 1986.

Young's agent, Leigh Steinberg, told the New York Times that the second-year player from Brigham Young, whose NFL rights are held by the Tampa Bay Buccaneers, has an option to leave the USFL because of what the attorney said is "a breach of contract."

Steinberg, Young and Young's father met for more than three hours Thursday with Usher to discuss the player's future. Steinberg said he expected to speak again with Usher by telephone within the next few days and that if Young chose to leave the USFL and the league sought to contest such a decision, he would consider filing a lawsuit to have the courts interpret Young's contract with the Express.

Young's four-year contract, signed in March 1984, is worth about $40 million, with most of the money deferred over many years. Steinberg said it contained a clause prohibiting J. William Oldenburg, then the owner of the Express, from transferring the contract to a new owner or to the USFL . . .

U.S. Football League owners met for 10 hours in Teaneck, N.J., to try to figure out how to remain solvent and in the public eye in its year's hiatus and resolved only to meet again Sunday.