The NFL has rejected sworn affidavits from Pittsburgh Steelers linebacker James Harrison, Green Bay Packers linebackers Clay Matthews and Julius Peppers and free-agent linebacker Mike Neal and has demanded to interview them at training camp, a source told ESPN's Adam Schefter.
The players wrote the affidavits in response to an Al-Jazeera America report that mentioned them in performance-enhancing drugs allegations.
The league rejected the NFL Players Association's view that affidavits constitute reasonable cooperation by the players and confirmed that they are required to participate in in-person interviews, the source said.
"The PED policy reflects the NFL and NFLPA's shared commitment to protect the fairness and integrity of the competition on the field, and we owe it to the players, clubs and fans to fully address any claims of this nature," a league source told Schefter.
The NFL advised the NFLPA that to move forward to resolve the allegations, the league would first interview Neal and then follow with the other player interviews.
The Packers open camp Tuesday, and the Steelers open camp July 29.
In his affidavit, Harrison said he has never violated the league's policy on performance-enhancing drugs and also has never met the man who alleged to Al-Jazeera America that he supplied him with an illegal substance.
The affidavit, dated July 11, 2016, was included with a letter from Heather M. McPhee, the NFLPA's associate general counsel, to Adolpho Birch, the NFL's senior vice president of labor policy.
The union included the affidavit, along with a transcript of the only references to Harrison in the Al-Jazeera report, to support its position that there is no need for Harrison to agree to an in-person interview with the NFL as the league lacks evidence to support such an interview.
Charlie Sly -- the source for the Al-Jazeera report that implicated the four aforementioned players, as well as retired quarterback Peyton Manning and athletes from other sports -- has since recanted his remarks. The NFLPA has argued that because of that, the players should not have to discuss the matter with the NFL. Birch has previously disputed the relevance of that argument.
The Al-Jazeera America documentary "The Dark Side" aired last December. In the transcript, which was provided by the NFLPA with the letter, Sly tells an undercover reporter that he supplied Harrison with a substance named D2 or Delta-2.
Harrison, however, says in the affidavit that to the "best of my knowledge and recollection, I have never met the individual who is apparently named Charles Sly, whose remarks appeared" in the report.