"I'm very pessimistic. I think there's going to be a strike," Kenneth F. Moffett, the federal mediator in the baseball negotiations, said yesterday.

Representatives for the owners and players talked for about an hour in New York yesterday but they might as well have been trading baseball cards for all they accomplished. Asked if there had been any progress that might avert a strike on May 29, Moffett said simply, "Zero." Talks resume today.

"Anytime you have a situation where there is a take-away issue, you always stand a risk of having a strike," Moffett said. "Something previously won by the union is not easily given up."

Moffett, of course, was referring to the single issue in the negotiation: free agent compensation. The owners want a form of compensation that would reward a club losing a free agent with another major league player; the only current form of compensation is a pick in the annual amateur draft.

After negotiations recessed yesterday, representatives of the Major League Players Association flew to Washington to meet with the general counsel of the National Labor Relations Board (NLRB). Representatives for the owners met with William Lubbers, general counsel for the NLRB, Wednesday to discuss the charge of unfair labor practices that has been filed by the players association.

The players have requested an order compelling the owners to furnish data on the financial status of the 26 clubs and an extension of the May 29 strike deadline, in the event that information is made available to them.

Lubbers said he did not expect to make his decision on whether to file a complaint on the players' behalf before Tuesday.