Ongoing differences between NFL owners and players on economic issues have slowed negotiations and made a settlement of their contract talks by Friday's deadline appear increasingly out of reach, sources on both sides of the labor dispute said Wednesday.

Only a major change in the dynamics of the talks in coming days could make a settlement this week a significant possibility, the sources said.

A third postponement of the deadline remains possible, said the sources, who spoke on the condition of anonymity because the deliberations are at a sensitive stage. But some in the sport were bracing for the unraveling of the talks.

It would take movement in the bargaining or another late-week development, according to the sources, to keep players from moving to decertify their union Friday and seeking a court injunction to try to block a lockout Saturday by the sport's franchise owners.

Talks resumed Wednesday morning in Washington. The two sides continue to battle over how much financial data the owners should reveal to players. One source familiar with the deliberations said Wednesday that the league offered the union five years of annual audited NFL profitability data for the 2005 to 2009 seasons. The data would not have disclosed annual profits or losses for each team, the source said, but would have given the combined profits of the 32 teams. It also would have listed the number of teams that posted better or worse results relative to the previous year.

Under the league's offer, an independent auditor would have been chosen to verify the data. According to the source, such data is not even available to the teams.

The union rejected the offer, the source said. Other sources have said the union is seeking full audited financial statements for each of the teams covering a longer span, perhaps as much as 10 years.

Wednesday afternoon, as he left the bargaining session, Kevin Mawae, president of the NFL Players Association, told reporters the league's offer for financial disclosure was insufficient.

"We've asked for financial transparency and audited financials since May 2009," Mawae said. "And anybody that would report that we've gotten that information and rejected it is simply not telling the truth."

The two sides also remain far apart on how to divide the approximately $9 billion in revenue the NFL takes in each year. The NFL also has proposed lengthening the regular season from 16 to 18 games, imposing a rookie wage scale and blood-testing players for use of human growth hormone.

The players' appeared poised to decertify their union last Thursday when last-minute movement in the negotiations allowed federal mediator George Cohen to persuade the two sides to keep talking. They ultimately extended talks until this Friday at 11:59 p.m. But because of court deadlines, the union would have to decertify by late Friday afternoon.

Decertifying the union would enable the players to file antitrust litigation against owners. If they made that move, the players' side also is likely to go to U.S. District Judge David Doty's Minneapolis courtroom seeking to block a lockout that could begin as soon as Saturday. The NFL hasn't had a work stoppage since players went on strike in 1987.