An NFL spokesman said Friday that an unknown number of unnamed players have been suspended due to positive tests for human growth hormone, according to ESPN's Chris Mortensen.
The league started testing for HGH in 2014, but no player has knowingly been banned due to its use.
HGH use made headlines in 2015 when an Al Jazeera report claimed Peyton Manning, among other high-profile players such as Clay Matthews and Julius Peppers, used the performance-enhancing drug - though all were cleared by an NFL investigation.
That same year, former NFL quarterback Brady Quinn estimated that 40 to 50 percent of current players used HGH.
