The NFL Players Association wants to see evidence supporting the league's investigation into charges of dope cheating made in a December report by Al-Jazeera America on performance-enhancing drugs. The union's formal request was revealed Wednesday in letters sent to Adolpho Birch, the NFL vice president who sent letters to the union last week asking to investigate the four remaining active NFL players mentioned in the report -- Pittsburgh Steelers linebacker James Harrison, Green Bay Packers linebackers Clay Matthews and Julius Peppers and free agent linebacker Mike Neal. "On behalf of Mr. Harrison, we have repeatedly requested that the NFL inform him and the NFLPA whether the NFL possesses any credible evidence (e.g., verified documents or verified testimony of witnesses) that warrants an interview of Mr. Harrison regarding a potential violation of the Policy on Performance Enhancing Substances (PES Policy)," the union's letter on behalf of Harrison said, according to a copy obtained by USA Today.
