NEW YORK (Reuters) - A federal appeals court on Monday upheld the National Football League’s estimated $1 billion concussion settlement with thousands of retired players, calling the agreement imperfect but fair.

The NFL logo and set are seen at New York's Radio City Music Hall before the start of the 2013 NFL Draft April 25, 2013. REUTERS/Shannon Stapleton

A small group of players had objected to the deal, which was approved in April 2015 by U.S. District Judge Anita Brody in Philadelphia, because it did not cover potential victims of a degenerative brain disease that scientists have linked to repeated blows to the head.

“It is the nature of a settlement that some will be dissatisfied with the ultimate result,” Circuit Judge Thomas Ambro wrote for a three-judge panel of the 3rd U.S. Circuit Court of Appeals in Philadelphia. “But they risk making the perfect the enemy of the good.”

Steven Molo, the lead lawyer for the objecting players, said in an email his clients were disappointed and would consider their legal options.

Samuel Issacharoff, a lawyer for players who accepted the agreement, said the decision would ensure that players who urgently need help will finally get it.

“We are dealing with a situation in which NFL players are hurting,” he said in a phone interview. “We are going to give people serious compensation for truly terrible injuries.”

A spokesman for the NFL did not respond to a request for comment.

The settlement calls for payments of up to $5 million each to former players diagnosed with certain neurological disorders, but it does not address chronic traumatic encephalopathy (CTE), which has been linked to concussions.

The lawsuit was brought on behalf of more than 5,000 retired players, though the settlement could cover more than 21,000 former players, according to the court.

Roughly 200 retirees objected to the agreement, saying it did not account for CTE. They also argued the deal unfairly favored currently injured retirees and left thousands of former players who have not yet been diagnosed with neurological diseases without a remedy.

CTE has been discovered during autopsies for several former players, including Hall of Fame linebacker Junior Seau and Pro Bowl safety Dave Duerson, who both committed suicide. In March, the NFL for the first time acknowledged a link between football and CTE.

But the appeals court noted that the research surrounding CTE is still nascent, with no current way to test for the disease while an individual is still alive. It also said many of the symptoms associated with CTE, such as memory loss, are eligible for compensation under the settlement.