Baseball negotiators were having another talk on the mound into the wee hours of Friday morning, the day of a strike deadline when the great American pastime could be declared a washout.

"It will be a late night, pizza, soda-adrenaline night," Texas Rangers player representative Jeff Zimmerman said. "Negotiations are really sensitive now. It's hard to express optimism or pessimism."

In a conference call with union leaders late Thursday, players were told progress had been made but that the sides were still apart, two people familiar with the call said on condition of anonymity.

"We're just going to keep working," said Bob DuPuy, baseball's chief operating officer. "I've been prepared to stay for the night all week."

Lawyers for both sides, carrying proposals and umbrellas, shuttled between the commissioner's office and union headquarters in the rain.

There was no set time for the start of a strike, which would be the sport's ninth work stoppage since 1972. The first game affected would be St. Louis at Chicago, which is scheduled to begin at 3:20 p.m. EDT. Fourteen games are scheduled at night, but the union told players not to report if an agreement isn't reached.

After five bargaining sessions Wednesday and three on Thursday, the sides remained apart on the key issues: levels for a luxury tax and revenue sharing. Other unresolved issues were the owners' desire to fold two teams and the expiration date of any new settlement.

The main talks resumed just before 9:30 p.m. and continued past midnight. In California, Tampa Bay and Anaheim were still on the field, playing what might be the final game of an abbreviated season. At about midnight EDT, after fans sang "Take Me Out to the Ball Game," they chanted "Don't Strike, Don't Strike."

"It's weird. Everybody's wondering what's going on," said Cincinnati Reds pitcher Jose Rijo, who bought tickets to fly home to Miami on Friday despite a scheduled home game.

The walkout threatens the final 31 days and 438 games of the regular season, and imperils the World Series -- canceled by a strike in 1994 for the first time in 90 years. If a strike drags into mid-September, the postseason would be jeopardized.

Many fans vented their frustration with signs at Thursday's 10 games, perhaps the last ones of the season.

In the upper deck at Cincinnati, one banner said, "There's No Crying In Baseball."

"Both sides are being awfully greedy, considering what is happening economically in this country," said Mary Anne Curran, a fan at the Pirates-Braves game in Pittsburgh. "I find it disgusting they can't find a happy medium when they're talking about millions of dollars."

Atlanta pitcher Tom Glavine, the NL player representative, arrived at the union office in New York after the game.

"There's going to be a lot of posturing. Nobody is going to show their best hand until they have to," he said.

A spokesman for President Bush, former owner of the Texas Rangers, said the White House wouldn't get involved.

"This is something the players and owners need to resolve," said White House deputy press secretary Scott McClellan.

He added that Bush wanted owners and players "to keep in mind not only what a strike would do to the future of baseball, but also what it would to America during a time of national unity and national spirit."

Pennsylvania Sen. Arlen Specter, a senior Republican on the Judiciary Committee, asked the panel's chairman to schedule hearings on revoking baseball's antitrust exemption if players strike.

"If baseball is determined to kill the goose that lays the golden egg, Congress should send a clear message to the owners and players for a plague on both your houses," Specter said in the letter to Sen. Patrick Leahy, D-Vt.

At the ballpark Bush helped build in Arlington, Texas, the Rangers' clubhouse was filled with boxes for players' belongings.

"It doesn't sound real good from what I've heard in the last few hours," said Rangers shortstop Alex Rodriguez, who would lose the most of any player, $114,754 a day. "You just have to prepare yourself for the very worst."

The old contract expired after the World Series last November, and talks for a new deal began in January. Commissioner Bud Selig, upset in recent years by the domination of the New York Yankees and other wealthy teams, wants to increase the amount of locally generated revenue teams share from 20 percent to 36 percent. Players have proposed 33.3 percent and want to phase in the increase.

To slow salaries, owners have asked for a luxury tax that would penalize high-spending teams. The sides got closer Thursday, with owners increasing the proposed threshold for the tax to $112 million, an increase of $5 million, a player representative said, and the union lowering its threshold an equal amount to $120 million.

The Associated Press contributed to this report.