Their appeal echoes their previous complaints some players won't be fairly compensated under the settlement, which would cover nearly 20,000 retired players for 65 years.
Senior U.S. District Judge Anita Brody has granted preliminary approval pending a November fairness hearing. 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.
Lawyers who negotiated the deal say Monday's appeal to the 3rd U.S. Circuit Court is premature. They say they fear it will delay final approval and leave families in need waiting longer for their awards.