By Simon Evans
MIAMI (Reuters) - The NFL Players Association (NFLPA) has approved a new league drug policy following a vote on Friday that will allow testing for human growth hormone (HGH) for the first time, starting this season.
The new policy also raised the threshold for positive results for marijuana and also re-classified the punishment for use of amphetamine during the off-season, the NFLPA said in a statement.
Previously the use of amphetamines were considered performance enhancing drugs by the league but now their off-season use will be penalized as 'substance abuse'.
The policy is 'retroactive' and so allows for some players who were banned for amphetamine use during the most recent off-season to have their suspensions lifted.
The league's website, NFL.com, said that around 20 players could be instantly affected by the deal. Denver Broncos receiver Wes Welker could have his amphetamine ban revoked while Cleveland Browns All-Pro receiver Josh Gordon may see his one year ban cut to 10 games, the website suggested.
The policy must now be finalised between the league and union negotiators although it could take a while to reach an accord after NFL spokesman Greg Aiello admitted barriers remained.
"We have not yet reached an agreement with the union on revisions to our drug programs. There continue to be significant unresolved issues," Aiello said on his verified Twitter account after the NFLPA had earlier hailed the breakthrough deal.
"This is an historic moment for our players and our league," NFLPA President Eric Winston said in a statement after player representatives voted for the changes.
"We have collectively bargained drug policies that will keep the game clean and safe, but also provide our players with an unprecedented level of fairness and transparency. Players should be proud of their union for standing up for what was best for the game."
The NFL had struggled to find agreement with the union over HGH testing since including the item in the collective bargaining agreement signed in August 2011.
According to the NFLPA, the agreement allows for testing for HGH in the 2014 season but their statement said "players have the right to "challenge any aspect of the science of the HGH isoforms test. The collection of blood specimens is prohibited on game days."
Another new element in the deal will see the introduction of an independent arbitrator to handle appeals of positive tests.
The league and the NFLPA will jointly select, approve and pay for the retention of three to five arbitrators.
The union said they had successfully rejected a bid by the league to issue discipline for the arrest of driving under the influence of alcohol, prior to adjudication.
Instead a two-game suspension will be issued upon conviction or plea agreement for violations of law involving alcohol and driving.
"We stood up and fought for what was right," NFLPA executive director DeMaurice Smith said.
(Editing by Gene Cherry and Greg Stutchbury)