The Department of Justice accuses former NFL players, including Clinton Portis, of defrauding the league's health plan for more than $3 million. (1:57)

Former Washington Redskins running back Clinton Portis, who was among 10 former NFL players charged Thursday in a multimillion-dollar scheme to defraud the league's health care benefit program by submitting false claims for medical equipment, turned himself in to authorities in North Carolina on Friday.

Portis is expected to make an initial court appearance later Friday in Charlotte, according to Justice Department officials.

The players were charged in two separate indictments filed in federal court in Kentucky, accusing them of conspiracy, wire fraud and health care fraud. Prosecutors allege they submitted nearly $4 million in phony claims, leading to payouts of about $3.4 million between June 2017 and December 2018.

Portis' lawyer, Mark Dycio, said Thursday that his client "had no knowledge that his participation in what he believed to be an NFL-sanctioned medical reimbursement insurance program was illegal."

"He is completely taken aback by the indictment and will move forward with the process of clearing his good name and those of his fellow NFL alumni," Dycio said.

Also among those charged was former Redskin Carlos Rogers.

Prosecutors allege the players targeted the Gene Upshaw NFL Player Health Reimbursement Account Plan, which was established as part of a collective bargaining agreement in 2006. It provides tax-free reimbursement of out-of-pocket medical care expenses that were not covered by insurance and that were incurred by former players, their spouses and dependents.

"As outlined in the indictments, a group of former players brazenly defrauded the plan by seeking reimbursements for expensive medical equipment that they never purchased," said Assistant Attorney General Brian Benczkowski, who leads the Justice Department's criminal division.

The players claimed to have purchased hyperbaric oxygen chambers, ultrasound machines and electromagnetic therapy devices that were designed to be used on horses, he said.

Prosecutors say the group's alleged ringleaders, Robert McCune and Correll Buckhalter -- who they allege broke off to create his own similar ring -- would recruit former players by offering to submit fake claims to the health care plan. The ringleaders would then demand thousands of dollars in kickbacks for each fake claim, prosecutors allege.

The suspects are accused of fabricating letters from health care providers about using the medical equipment, fabricating prescriptions that were purportedly signed by health care providers and creating fake invoices from medical equipment companies in an effort to prove the equipment was purchased, according to court documents. In reality, they had never purchased or received the medical equipment, prosecutors said.

Investigators believe the defendants had forged the prescriptions and authorization letters, and they uncovered no evidence that any doctors were complicit in the scheme, Benczkowski said.

After the phony claims were submitted, the former players would receive reimbursement checks and pay a kickback to the ringleaders and recruiters, the indictments charge.

Prosecutors moved to bring charges, in part because the scheme put the health care plan's tax-exempt status at risk, which could have forced other former players using the plan legitimately to pay more, Benczkowski said.

Four of the suspects -- McCune, Rogers, John Eubanks and Ceandris Brown -- were arrested Thursday morning by the FBI. Six others, including Portis, agreed to surrender to authorities, the Justice Department said. The others are: James Butler, Frederick Bennett, Etric Pruitt, Tamarick Vanover and Buckhalter.

The Justice Department has also filed court papers in Kentucky noting that it plans to file charges against two other players -- Joe Horn, a four-time Pro Bowl wide receiver for the New Orleans Saints, and Donald "Reche" Caldwell.

The investigation was continuing, but because the plan involves only former players, prosecutors do not expect any current NFL players to face charges, Benczkowski said.

The Associated Press contributed to this story.