Re-establishing the union and figuring out exactly what it will take to for nine NFL players including Tom Brady to settle their antitrust suit against the league are among key issues blocking a deal to end the lockout, people familiar with the negotiations told The Associated Press on Saturday.

Even after owners and players made significant progress this week, potential sticking points remain, according to the people, who spoke on condition of anonymity because the talks are supposed to remain confidential.

The unresolved matters also include how the TV networks case, in which the players accused the owners of setting up "lockout insurance," will be settled.

Among the parts mostly squared away:

— how the more than $9 billion in annual league revenues will be divided;

— a rookie salary system;

— free agency rules.

The NFL’s first work stoppage since 1987 began in March, when owners locked out players after negotiations broke down and the old collective bargaining agreement expired. The NFL Players Association announced it was dissolving itself and would no longer be a union that could bargain for all players under labor law, instead saying it was now a trade association. That allowed players to take their chances against the NFL in federal court under antitrust law, and star quarterbacks Brady, Peyton Manning and Drew Brees were among those who did.

There is a possibility that the sides will be able to put together a tentative agreement in principle in time to keep the preseason completely intact. The exhibition opener is scheduled to be the Hall of Fame game between the St. Louis Rams and Chicago Bears on Aug. 7, and as of Saturday, no preseason games had been canceled.

The league’s owners have a special meeting set for Thursday in Atlanta, where they potentially could ratify a new deal — if one is reached by then. Any agreement also must be voted on by groups of players, including the plaintiffs in the antitrust suit and the NFLPA’s 32 team representatives.

Members of the legal and financial teams for the two groups met in New York on Saturday, while NFL Commissioner Roger Goodell and NFLPA head DeMaurice Smith spoke with each other. The larger negotiating teams that gathered for more than 30 hours of intensive face-to-face talks spread across Wednesday through Friday — including owners and current or former players — did not meet Saturday.

The court-appointed mediator, U.S. Magistrate Judge Arthur Boylan, has been on vacation but previously ordered both sides to meet with him Tuesday, when the framework for a deal could be concluded.

"The parties will be in touch with Judge Boylan to give him a report on developments in advance of next Tuesday’s session and will consult with him on how to make the best use of the time before our league meeting on Thursday," NFL spokesman Greg Aiello wrote in an email.

Among the parts of the deal that people familiar with the negotiations told the AP are largely in place:

— The players’ portion of the league’s full annual revenues will be on a sliding scale with a floor of 46.5 percent and a ceiling of 48.5 percent. There no longer will be the old formula, under which owners got a cut off the top for various operating expenses before revenues were divided.

The new percentages represent a decrease for players, because they were winding up with a higher percentage under the old contract, which is among the main reasons spurring owners to opt out of that deal. According to NFLPA figures, the players got 52.7 percent of all league revenues in 2006, 51.8 percent in 2007, 51 percent in 2008, and 50.6 percent in 2009. There was no salary cap in 2010. As far back as 2000, meanwhile, the players’ take was 56.5 percent of all revenue.

The players are still hoping, though, to get a commitment from owners that each team will spend a minimum amount of the cap.

— Most players will be able to become unrestricted free agents after four years in the league, and the owners’ hope for being able to get a right of first refusal on three players per team in 2011 was dropped.

— First-round draft picks will sign four-year deals, with a club option for the fifth year. The new rookie salary system will help curtail first-year players’ soaring salaries, with much of that money going to veterans.