Negotiations between baseball's owners and players will resume Monday at 2 p.m. in an effort to avert a strike that now could come, at the earliest, next Thursday.

Barring a settlement, hearings on the National Labor Relations Board's petition for an injunction will begin Wednesday morning in Rochester, N.Y., before Judge Henry F. Werker.

Representatives of the NLRB went into court Thursday, expecting to seek a temporary restrainign order from Werker that would have extended the strike deadline that had been set for today. Don Fehr, the general counsel of the Major League Players Association, said it was not until the negotiators got into the courtroom that the informal agreement between the players and the owners postponing the strike deadline was worked out.

Although some saw a hint of progress in the agreement, lawyers say such agreements are not unusual, especially when the granting of the court order is a virtual certainty. Fehr said, "They voluntarily agreed to do what they would have had to agree to anyway. I do not think it is significant in resolving the litigation or the underlying suit."

After the agreement was announced, federal mediator Kenneth E. Moffett said he did not think there would be any negotiations until after the judge had ruled on the injunction. But, after talking to both parties, Moffett scheduled a session for Monday.

Ray Brebey, the chief negotiator for the owners, said, "I asked for a meeting. This (the legal proceeding) isn't going to solve the issue (free-agent compensation) if it ends two years from now. The issue still has to be resolved."

There are those familiar with the situation who believe that the owners, who have been accused of failing to bargain in good faith, may want to meet in part to convince the judge and the NLRB that they are, indeed, bargaining in good faith.

Others speculate that there may be movement in the negotiations prompted by the impending legal proceedings, including the NLRB hearing scheduled for June 15, that will determine whether the owners must turn over their financial records. There are those who say they would not be surprised if the owners made a new proposal on compensation at the bargaining session Monday.

Marvin Miller, the executive director of the players association, said, "My feeling from yesterday is that they're still stonewalling it . . . Obviously, they are going to fight the injunction. What happens if they win? There will be a strike in 48 hours. What does that say to you?"

The informal agreement worked out between the owners and players gives the players the right to strike not earlier than 24 hours or later than 48 hours after Werker rules on the request for the injunction. Thursday night, the executive board of the players association unanimously voted to strike within 48 hours if the injunction is not granted.

Because of Werker's schedule, which requires him to preside over a criminal trial and the hearings simultaneously, it is difficult to predict how long the hearings could last. Al Blyer, an attorney in the New York office of the NLRB said, "The judge has indicated that he may not be able to give us full days Wednesday or Thursday. He promised an expeditious hearing and decision."

Some of the facts the NLRB attorneys will be relying on are those statements by owners concerning the precarious financial state of the game, statementss that the players included in their unfair-labor-practice charge.

The players pointed to those statements as evidence that the owners' real interest in achieving compensation is to drive down salaries. They say if the owners cannot afford the salaries, they should have to provide documentation to prove it.

Fehr said it was his understanding that the attorneys for the owners' player relations committee may call some of the owners to the stand to explain those statements.

Grebey said today he had no comment on the conduct of the trial. But John McMullen, owner of the Houston Astros, had plenty of comments about the NLRB proceedings. He told the Houston Chronicle they were "a subterfuge and a charade cleverly orchestrated by the players association."

McMullen said, "I've been involved in a number of labor disputes in my life and I've found that the NLRB tends to be pro labor. It's not correct to think that a private industry should be exposed this way. Players shouldn't have the right to see how much money they should be asking for from their employes. But this theory, the president of the United States should be given a percentage of the national budget."

McMullen said those who saw the NLRB's actions as a victory for the players were mistaken. "I believe they will find out otherwise in the long run," he said. "This has opened up a new wound, a wound that can only fester in the future."