A federal appeals court upheld the NFL's $1 billion settlement with former players on Monday despite objections by some that the deal does not do enough to address certain medical issues.

The U.S. Third Circuit Court of Appeals in Philadelphia unanimously upheld the agreement approved in April 2015 by U.S. District Judge Anita Brody that resolves numerous lawsuits against the NFL by retired players suffering from the effects of brain trauma.

The deal was challenged by some former players because it excludes compensation for the effects of chronic traumatic encephalopathy, or CTE, the brain disease increasingly found in former players. The NFL argued that the science linking CTE with football is still in the early stages, though league executive Jeff Miller acknowledged a connection in testimony on Capitol Hill last month.

Ultimately, the court wrote that the objectors "risk making the perfect the enemy of the good" in ruling the existing settlement to be better than the former players potentially getting nothing.

"This settlement will provide nearly $1 billion in value to the class of retired players," the judges wrote. "It is a testament to the players, researchers, and advocates who have worked to expose the true human costs of a sport so many love. Though not perfect, it is fair."

The settlement provides for payments to be made on a sliding scale depending on the medical conditions of former players, with the most money reserved for those suffering from Lou Gehrig's disease, Parkinson's disease and other more serious neurological ailments.