Anita Brody

NEW YORK — The NFL may be on the hook for more money than it expected if a federal judge can’t be convinced that its $765 million concussion settlement with more than 4,500 former players will be adequate to pay out benefits over the 65-year life of the agreement.

The deal hit a snag Tuesday when a federal judge asked both parties to back up their assertions that the agreement is appropriate.

U.S. District Judge Anita Brody denied a motion that was meant to serve as a preliminary approval for the settlement, seeking more information.

She wrote that she was “primarily concerned that not all retired NFL football players who ultimately receive a qualifying diagnosis or their (families) ... will be paid,” and that the lawyers for both parties have not addressed those concerns.

Given the judge’s ruling, the two sides will need to offer more evidence the fund will be sufficient or possibly have the NFL add money to the pot. Otherwise, they may be left to start over.

“We are confident that the settlement is fair and adequate, and look forward to demonstrating that to the court,” NFL spokesman Greg Aiello said.

Meanwhile, former players looking to receive assistance for the injuries they sustained will have to wait to be compensated.

The two sides agreed in late August, just before the season kicked off and the issue largely went to the back burner, awaiting Brody’s decision. The weekly accounting of brain injuries on the field, despite efforts to reduce them, continued to make headlines.

Brody pointed out that the class of about 20,000 could overwhelm the fund, even if only 10 percent of its members file claims against the $675 million set aside to pay claims, working out to $337,500 per player.