The two current players said they had been treated by Anthony Galea — who specializes in the field of plasma therapy, or "blood spinning," designed to speed healing of injuries — but they said they didn't ingest human growth hormone (HGH).

Galea — whose patients included Tiger Woods and Alex Rodriguez, both of whom have denied taking HGH — was charged Tuesday with smuggling, unlawful distribution of HGH, conspiring to lie to federal authorities and introducing an unapproved drug, actovegin, a derivative of calf's blood used to speed healing, into interstate commerce.

The NFL issued a statement after the complaint was filed that said, in part, "We obviously have a very strong interest in learning who these players are and about their involvement with any prohibited substances so that we can enforce our policies. When we have had evidence of illegal purchase, possession or use of HGH, we have imposed discipline, and (we) are fully prepared to do so again if the facts support it."

Criminal defense attorney Chris Leibig said the players potentially could face misdemeanor charges of knowingly taking or possessing an illegal substance without a prescription. But he said their cooperation as witnesses boded well for them.

"If someone cooperated with the government, that person can hope to receive more benefits, like not even being charged at all," he said.

Leibig also said it was difficult to assess how much jail time Galea might be facing, given the variety of charges.

"If you're found to be the leader of a conspiracy," he said, "that can enhance (the penalty) even more."

Galea's attorneys didn't respond to telephone calls seeking comment.