(Reuters) - The National Football League has rejected written statements from four players named in a report alleging use of performance-enhancing drugs as sufficient cooperation and will need to interview them, the league said on its website on Friday.
Pittsburgh's James Harrison and Green Bay players Clay Matthews, Julius Peppers and Mike Neal have given written statements regarding a December report by Al Jazeera America that they received the illegal drugs from an anti-aging clinic.
The NFL Players Association has argued that there should be no need to interview someone based on an allegation that has no proven merit.
"The league responded to the union this afternoon confirming receipt of written statements by Matthews, Peppers, Harrison and Mike Neal," the NFL website cited an unnamed source as saying on Friday in a report.
"The league rejected the union's view that affidavits constitute reasonable cooperation by the players and confirmed that they are required to participate in in-person interviews."
The NFL will start with interviewing Neal, and plans to speak to Harrison, Matthews and Peppers on the first day of their respective training camps.
The Al Jazeera report cited a former unpaid Guyer Institute intern pharmacist, Charlie Sly, who allegedly spoke to an undercover reporter working for the network.
Sly later recanted his statements about the players receiving the drugs, and Harrison said he has never met him in an affidavit obtained earlier this month.
(Writing by Jahmal Corner in Los Angeles; editing by Sudipto Ganguly)