The NFL informed team owners Friday that testing for human growth hormone would not take place at the outset of the new season, The Washington Post reported.
In a memo sent to teams, the league said testing had been delayed because of the NFL Players Association's "refusal to accept the validity of tests" conducted by the same agency that monitors testing for the Olympics.
Blood testing for HGH had been worked into the NFL's new 10-year collective bargaining agreement, with the hope that random testing would begin by the first week of the regular season, but the two sides were unable to come to an agreement on how to implement the process.
"Although the CBA reflects a commitment to implement (HGH) testing by the start of the 2011 regular season, it is apparent that we will be unable to do so because of the (NFLPA's) continued refusal to accept the validity of the tests developed by the World Anti-Doping Agency that are used in Olympic sports and minor league baseball," NFL executive vice president of labor Jeff Pash wrote in the memo, obtained by The Post.
It remained unclear whether testing would be implemented further into the season, which kicks off next week. If blood testing is carried out, the NFL would become the first major US professional sports league to test its athletes for HGH.