Negotiations in the stalemated baseball contract talks have broken off.

Federal mediator Kenneth Moffett called a recess today in the talks between the Major League Players Association and the baseball owners.

Moffett said he would call another meeting before the Friday strike deadline set by the players. But, as he left to return to Washington, Moffett said he would definetly not be back Monday and probably not Tuesday either.

Marvin Miller, executive director of the players association, said he would spend the next two days preparing the players for a strike, which he said "seems to me extremely likely."

Asked what inning the negotiations were now in, Miller smiled grimly. When the same question was put to Moffett he said, "What did Marvin say?" When told, Moffett said, "Then we're both smiling."

Representatives of the players and the owners met face to face across a conference table the color of the infield and a rug the color of the outfield for less than five minutes. The remainder of the two sessions was spent in seperate meetings with the mediators.

The subject of today's talks was the owners' proposal that negotiations and the baseball season continue, subject to two conditions set forth by the owners: first, that a new contract, whenever is it reached, would apply retroactively to the beginning of the 1980 season; and second, that they would not declare an impasse in the negotiations before the start of next season.

In a prepared statement, Ray Grebey, chief negotiator for the owners, said, "With these proposals on the negotiating table, there is no peril to the players in the continuing negotiations.

"There is no factual reason for the interruption of the championship season."

After the talks broke off, Miller said, "They wanted to know what were the deficiencies of their nothing proposal, by which I mean their proposal that the players continue to work under a 4-year-old agreement."

Miller said the owners' proposal is "a clear attempt to con the players into playing the rest of the season with no improvements whatsoever and no assurances that any would be made. While the owners collect what 1980 gives them, the players are stuck with 1976 conditions."

Miller said that the owners' suggestion of an April, 1980 deadline was an attempt "to get the players to strike when the owners prefer the strike, in April (when gate receipts are lowest and losses would be minimized)."

As for the owners' promise of retroactivity, Miller said, "If I offer zero retroactively, it's still zero."

The talks have made zero progress on the owners' demand for compensation for the signing of free agents, the roadblock in the negotiations.

Under the 1976 agreement, the only compensation awarded to a team losing a free agent is a pick in the amateur draft. Under the owners' new proposal, if a premium free agent (one selected by seven or more teams and among the leaders at his position) is signed, the club signing him may protect 15 players. The club losing him can select anyone else from the other team's roster. For a free agent selected by seven or more teams but not among the leaders at his position, the club will be able to protect 18 players.

Miller stressed, as he has before, that the aim of the owners' compensation proposal "is to drive down salaries," but not necessarily those of the superstars. "For every $800,000 player there are 30 or 40 or 50 or so on down the line," he said, "where the real money is."

That, Miller says, is why the owners' proposal defines superstars as anyone in the top 50 percent.

The owners maintain that 20 percent of last year's free agents would have been considered premium according to this proposal. "Once you recognize the inconsistency of it and see they mean half you realize the fraudulent nature of it," said Miller. "If they designed a compensation plan that only affected Nolan Ryan it could be narrower."

Asked if that meant the players would be receptive to a compensation plan with a narrower definition of the premium free agent, Miller said, "No. I don't want to comment on that. It has never been before us."

But sources close to the talks say that the definition of the premium free agent is the key to the negotiations. A proposal from the owners that more narrowly defined the premium free agent might have been more acceptable to the players, they say.

Other sources agree that a more narrow proposal might have been better received, but only if the owners were able to justify the need for it based on the health of the industry. That, the sources say, would be difficult to do given the lucrative new television contract signed with the networks and the increase in ticket sales.

The players regard the compensation proposal as a demand for a give-back, guaranteed to force a strike. At this late stage, they are reluctant to say what has been apparently true all among: increased compensation is essentially a non-negotiable issue.

Miller continued to protest actions of the owners' negotiating team, which he said included sending out a question-and-answer to two or three teams detailing why the players should not strike and thereby undermining the players association by going directly to the players.