Before dawn today, the 50th day of the baseball player's strike, a settlement was reached that will have players returning to practice Saturday Oakland A's President Roy Eisenhardt confirmed.

Although it had not been publicly announced, Eisenhardt said, "I was called at 11:25 p.m. (Pacific Daylight Time) by Clark Griffith of the Player Relations Committee. It is over. We have a settlement."

Eisenhardt said players would begin working out Saturday and would be paid during the period of the workout. Also, he said, that the All Star Game would be played Aug. 9 in Cleveland.

Eisenhardt said the players had received the full major league service credit that Marvin Miller, executive director of the Major League Baseball Players Association, said was etched in stone in exchange for a year extension of the Basic Agreement, which was due to expire at the end of the 1983 season.

There was no report on the resolution of the issue of free-agent compensation, which was at the heart of this, the longest strike in major league history.

Thursday began innocently enough with a negotiating session scheduled for 2 p.m. However, no one but federal mediator Kenneth E. Moffett showed up. About two hours later, Moffett, who was clearly taken by surprise himself, informed the press that some private, informal meetings were being held by the parties. "You can read anything you want into that information," he said.

Dick Moss, a consulting attorney for the players association, said, "It's a good sign. That's how deals are made."

Last year, when a strike was averted at the last moment, agreement was reached after several such "sidebar" meetings among Miller; Ray Grebey, the owners' chief negotiator; Commissioner Bowie Kuhn, and Moffett.

According to one source close to the negotiations, Thursday's initial private session included Miller, Grebey, Don Fehr, the general counsel of the players association, and American League President Lee MacPhail.

The source said the meeting "was requested by Grebey or one of his people. Marvin refused to have it alone and that's where it got to be MacPhail and Grebey. Marvin didn't like that, but he said he'd try it.

"The owners asked a lot of questions about how the players felt about the owners' last proposal. They wanted another session tonight."

The development came a day after the owners held several sessions, with each league meeting session, with each league meeting separately and then all 26 clubs meeting together. There was speculation the owners' negotiating committee had been given "new marching orders" to get a settlement.

There also was speculation from sources on both sides that MacPhail had assumed greater responsibility for the owners' bargaining team, as Grebey's authority had diminished.

Thursday night at 8, several players on the union's bargaining team -- Bob Boone of the Phillies, Mark Belanger of the Orioles, Doug DeCinces of the Orioles, Steve Rogers of the Expos and Phil Garner of the Pirates -- were seen entering the hotel. Around 9, the players left, presumably to confer with Miller at his office. There was speculation the two sides were caucusing.

Attempts to reach Moffett were unsuccessful; a security guard answered the telephone in his room.

Some sources close to the negotiations believe that the increased pressure for a settlement is partly because baseball is rapidly approaching the time when not only the 1981 but the 1982 season would be in jeopardy. No matter when this strike is settled, they say, this season will be regarded as an "asterisk" season, a waste. "The point now," as one source put it, "is to make next year viable."

Several owners have pointed out that if this season is lost, there will be no incentive for either side to negotiate during the winter, meaning nothing could be resolved until spring.

The owners' $50 million strike insurance policy, which has paid $100,000 per canceled game since the 153rd game of the strike, will run out Wednesday