PHILADELPHIA (AP) — Seven former professional football players have filed a court challenge to a tentative class action settlement of concussion claims that would cost the NFL at least $765 million.

They argued that some players won’t be fairly compensated under the plan, especially those whose awards would be reduced or negated because of prior strokes or other factors. Their appeal echoes their previous complaints about the plan, which would cover nearly 20,000 retired players for 65 years.

Senior U.S. District Judge Anita Brody has granted preliminary approval of the settlement pending a fairness hearing in November, when other critics can challenge it and perhaps decide to opt out and reserve the right to sue individually. Her approval came after the NFL agreed to remove the $765 million cap to ensure the fund doesn’t run out.

The group appealing the judge’s decision includes 2008 Pro Bowl player Sean Morey, now Princeton University’s sprint football coach. The group’s lawyers appealed the decision by Senior U.S. District Judge Anita Brody on Monday.

“Conflicts within the class leave many class members without adequate representation,” lawyer Steven F. Molo wrote in the appeal. “This class, as certified, is doomed.”

He noted that families of players diagnosed posthumously with the debilitating brain disorder chronic traumatic encephalopathy, or CTE, in the future would not receive the $4 million given to families that received the diagnosis before preliminary approval of the plan this month.

Instead, the players would be treated and compensated for the various symptoms they exhibit during their lives.

Plaintiffs’ lawyers who negotiated the settlement with NFL lawyers for more than a year called the appeal premature since the agreement has not been finalized.

“This petition is entirely without merit, and only serves to confuse and obscure the tremendous benefits retired players will receive if this settlement is approved by the Court,” lawyer Christopher Seeger said in a statement Tuesday.

The appeal was filed in the 3rd U.S. Circuit Court of Appeals.