NEW YORK (Reuters) - A federal judge has ordered the National Football League and its players to begin mediation under the auspices of a Minnesota court this week in a bid to resolve a dispute that threatens America's most popular sport.

Chief Magistrate Judge Arthur Boylan will meet with representatives of the players on Tuesday and the NFL on Wednesday with formal mediation to begin Thursday, Judge Susan Richard Nelson said in an order filed on Monday.

"Any communications conveyed between the parties in this process, shall not be admitted or used against any party in any other proceeding or forum, for any purpose," she wrote.

The comment appeared to address concerns by the players that new talks would result in the NFL Players Association being considered a union again.

The process also will not have the effect of a stay on litigation for a preliminary injunction now before the court, according to Nelson.

The players requested the injunction against the league's lockout of them. Their motions remain under advisement with an order to be issued in due course, Judge Nelson wrote.

Nelson, who presided over an April 6 hearing on the players' request and said she would make a ruling in a couple of weeks, also urged the two sides to meet in an attempt to resolve their differences.

The NFL had wanted the negotiations returned to the federal mediation service in Washington, where previous negotiating sessions on a new collective bargaining agreement were held.

The players, however, wanted the mediation held under court auspices in Minnesota.

The bargaining talks between the two sides collapsed on March 11 when the owners and players could not agree on how to divide the $9 billion in annual revenue.

Nine NFL players, including high profile quarterbacks Tom Brady, Peyton Manning and Drew Brees, then filed an antitrust lawsuit against the NFL and asked for an injunction against the league lockout of the players.

(Reporting by Gene Cherry in Salvo, North Carolina; Editing by Frank Pingue)