Negotiations between representatives of the striking major league baseball players and the team owners appear unlikely to be resumed before Tuesday following the first midseason weekend in the sport's history that all the ballparks were empty.

Kenneth Moffett, the federal mediator assigned to the case, said yesterday it was unlikely that the parties would resume negotiations before Tuesday morning. Moffett said he had a conflict that would prevent him from scheduling a session this afternoon and that talks tonight did not seem feasible because, as of last night, he had not been able to get in touch with the owners' Player Relations Committee.

At the White House, a spokesman said President Reagan has no plans to intervene in the strike, as suggested by Baltimore Orioles' owner Edward Bennett Williams.

"The president hopes the strike can be settled without his action," said spokesman Robert Gray. "There were also suggestions that he get involved in the coal strike, but he didn't."

Williams had told The Baltimore News-American that Reagan could ask that the key isue in the strike -- the unresolved question of free-agent compensation -- be sent to an impartial arbitrator for a decision.

In Baltimore yesterday, Williams said he would be in New York tonight and Tuesday to "see what's going on" in the negotiations.

"I want to talk to (Commissioner Bowie) Kuhn and (American League President Lee) MacPhail and find out what's happening," Williams said.

Williams declined to say publicly that he hoped to attend the next bargaining session, although he has said he believes he could help settle the dispute if given the chance.

Williams said he spent much of yesterday discussing with Oriole General Manager Hank Peters the aspects of the strike and how they will affect their team.

Peters is to announce the club's ticket-refund policy and answer related questions Tuesday at a news conference.

Oriole player representative Mark Belanger said, meanwhile, that "it may be time to take the offensive" if negotiations remain stalemated.

"They (the owners) could be fooling with danger," Belanger said. "We've said all along that we have no demands on the table, but that could change. We're out now and it's costing us money."

Belanger and teammate Doug DeCinces will make up half of the players' negotiating team in New York this week. They are to be joined by Steve Rogers of Montreal and Bob Boone of Philadelphia.

Meanwhile, as baseball's first midseason strike went on, estimated losses mounted into the millions of dollars in uncollected gate receipts, radio and television royalties and a variety of other baseball-related operations.

In Pittsburgh, Mayor Richard Caliguiri said the city suffered $100,000 in direct losses and $1 million in indirect losses -- the money people would have spent on motels, bars, restaurants and other services -- as a result of the canceled weekend series between the Pirates and the Los Angeles Dodgers.

"There is a direct impact on taxpayers," Atlanta Mayor Maynard Jackson said in Louisville during a break at the annual meeting of the U.S. Conference of Mayors.

Atlanta-Fulton County Stadium is jointly funded by the city and county and annually operates at about a $300,000 deficit, which must be covered by local tax funds, Jackson said. The strike, he said, can only increase the deficit.

In Detroit, the Tigers' weekend series against the Kansas City Royals had drawn the largest advance ticket sales of the season, and crowds totaling 90,000 to 95,000 had been anticipated. Officials estimate direct losses at the gate to be between $450,000 and $475,000.

In Minnesota, the Twins were scheduled to meet the New York Yankees, the American League's top draw, for three games over the weekend with attendance conservatively estimated at 60,000. Calvin Griffith, president of the Twins, estimated the total loss at $600,000.

Ticket sales and concessions for the series between the Expos and the Cincinnati Reds at Montreal's Olympic Stadium probably would have brought in $900,000, according to a team spokesman.

In Philadelphia, where first baseman Pete Rose had tied Stan Musial's National League hit record of 3,630, 55,000 had been expected to watch Rose attempt to pass Musial Friday night against the Atlanta Braves.

Overall, the Phillies said, cancellation of the weekend series with the Braves cost them $750,000.

Crowds of up to 110,000 had been projected for the weekend series in Milwaukee between the Brewers and the Chicago White Sox, and some estimates placed lost ticket revenue alone at $600,000.

However, Bud Selig, president of the Brewers, said he had no idea if the figures were accurate. "We haven't begun to make those assessments yet," Selig said. "It's impossible to say at this point what the losses would be." s

And, an official of the players association pointed out, the figures. quoted from lost ticket and concessionaire sales are not "true losses" because the clubs also were not paying the salaries of the players or the ancillary personnel needed to staff a ballpark.

In California, Arthur (Red) Patterson, an official of the California Angels, said, "We expected about 120,000 people for the three games (against the Boston Red Sox this weekend). You can multiply that by about $4 for what it means in money lost to the Angels.

"Overall, the two teams and the city (of Anaheim) lost about $5, maybe closer to $5.50, per person, including 20 percent going to the Red Sox."

Based on advance sales in Oakland, the weekend series between the A's and the Cleveland Indians had been expected to draw about 100,000 to 110,000 to Oakland-Alameda County Coliseum.

And the Indians are afraid the strike could cause cancellation of the All-Star Game, scheduled for July 14 in Cleveland.

"I'd hate to see it slip away," said Bill Murray, a representative of Kuhn. "I'm sure we'd do the best we culd to hold a game this year. We might even look to a different date, if it could be worked out. We just have to see when the strike is over."

And as baseball fans looked elsewhere for something with which to occupy their weekends, many long associated with the game found themselves spending an unaccustomed summer weekend at home.

"It feels funny being here now," said New York Yankee Coach Yogi Berra, who has spent the last 35 years in the major leagues as a player, manager or coach. "Like I should be wearing a uniform somewhere. It's the first weekend I've had off during the summer in I don't know how many years."

But, the strike also had its bright side.

For the Toronto Blue Jays, who through inept play edged out the Chicago Cubs as the worst team in the majors Thursday, the day before the strike, the walkout was viewed as possibly a welcome break in what so far has been a disastrous season: The Blue Jays had lost 11 straight, had the worst winning percentage in the majors at .276 and had a team batting average of .218.

"Maybe the strike will be helpful to us," said team player representative Al Woods. "I think a few of the guys were getting tense and that the pressure was getting on them. They were edgy. Maybe after a break, they will come back and play better baseball." Woods, an outfielder, had seen his batting average drop almost 100 points from the .300 he hit to lead the Blue Jays a year ago.

Both Ray Grebey, head of the Player Relations Committee, and Donald Fehr, chief counsel to the players association, had said they were ready to resume negotiations, which were broken off Friday for the weekend.

"We're available anytime Ken wants to call us," Grebey said