Bill Martin may be heading for court, but the rest of baseball has left it, at least temporarily, as hearings on the National Labor Relations Board petition for an injunction ended today.

Judge Henry F. Werker said he did not anticipate making a decision before Monday. The injunction would prohibit the owners from implementing their free-agent compensation plan until next spring.

Werker had originally said he would rule 48 hours after the close of the hearings. He said today he would extend that deadline to give himself time to study the record. As a result, the players, who have the right to strike 24 to 48 hours after the decision, could not do so until early next week.

Meanwhile, federal mediator Kenneth E. Moffett announced that Marvin Miller, the executive director of the players association, and Ray Grebey, the owners' chief negotiator, had agreed to resume talks in New York at 2:30 p.m. Friday.

But today, most of the talks was from the lawyers. In their closing arguments, Louis Hoynes, attorney for the National League, and Joseph Mayer, the assistant general counsel of the NLRB, conceded the extrordinary nature of both the case and the relief that the NLRB has requested on the players' behalf.

In an extrordinary press interview later, Werker said, "It's as extraordinary as throwing a manager out of a game."

When the reporters told him that was no longer an unusual measure, he replied," It isn't now but it used to be. Billy Ball has changed all that."

Closing arguments began at 10:15. Hoynes went first, characterizing the players' unfair labor practice charge with the NLRB as a "sham, a diversion and an attempt to avoid the obligations of the union as expressed by the 1980 collective bargaining agreement."

Hoynes said the complaint issued by the NLRB on the players' behalf is "fuzzy and novel," as well as factually unsupportable.

He argued repeatedly against the players' contention that the owners had injected their inability to meet soaring player salaries, saying that claim made "no sense at all." He then cited several owners, whom he called "captains of industry," and alluded to their assets. "There can be an unwillingness to pay, to refuse to be silly, and they are indications of that, but an inability? It's impossible to conceive of that."

While barely mentioning the speech of Commission Bowie Kuhn on the dire financial prospects of baseball, which is the centerpiece of the players' case, Hoynes dismissed the newspaper articles ("a half-dozen among thousands") submitted as evidence by the NLRB. The articles contained statements by owners tying free-agent compensation to the health of the game. "To treat it as the collective bargaining position is absurd," he said.

One of the keys in the case is whether Kuhn is an agent of the owners, who yesterday tried to disavow his role in the collective bargaining process, and whether Grebey can disavow statements the owners have made to the press.

Mayer said, "The principals (owners) have raised the doubt (about finances), not the agent. Only the agent (Grebey) can relieve it . . . If the respondents can't control their members' tongues that the responsibility should not fall on the union."

Don Fehr, the general counsel of the players association, made the same point. Initially, the judge ruled that Fehr would not be given an opportunity to speak but reversed himself because, he said, "Fehr looked so forlorn."

Sounding anything but forlorn, fehr said, "Who is the union to believe? Are we to assume because Mr. Grebey says, 'Who's Mr. Kuhn and the rest of the owners?' that that solves the question? We don't think so. If the (financial) problems are real, we've got to know it and take it into account (in negotiations)."

In deciding whether to issue the injunction, the judge must decide whether there is reasonable cause to believe the National Labor Relations Act has been violated.

Mayer pointed out that the NLRB could have requested an injunction ordering the owners to turn over their books and records but chose not to. He urged the judge to issue the injunction that he said would maintain "equilibrium" until the merits of the case can be decided by an administrative law judge in a hearing scheduled to begin June 15.

When Mayer argued that the injunction would do the least possible harm to both parties, by putting off implementation of the compensation plan for a year, the judge replied: "It's a denial of a contractual right they have bargained for . . . The union got the right to reopen the agreement and to strike."

"And," said Mayer, interjecting, "to negotiate in good faith on this issue, which they have been denied."

Lawyers familiar with the case say that many judges, particularly those in this district, consider issuing such injunctions to be anything but routine. That impression was reinforced by Judge Werker, who repeatedly interrupted Mayer's argument with questions on the issues. At one point, the judge told Mayer, "You've shown nothing, nothing, by way of evidence that the (financial) issue was raised at the bargaining table."

Mayer concurred but said the situation was unusual enough to demand a preliminary injunction.

"It is preliminary but it is also extraordinary and unusual," the judge replied.

"Your honor," Mayer said, "I agree it is extraordinary relief but we feel extraordinary relief is needed in extraordinary cases."

Although many spectators think the tough questioning bodes ill for the NLRB, lawyers for both sides, as well as the judge, deny it. "I was just trying to clarify my own thinking," Werker said.