NEW YORK — Hours after the players’ union voted Friday to accept an NFL proposal on drug policy changes that included HGH testing, the league says it is not a done deal.

Player representatives to the union also voted for changes to marijuana testing, classification for amphetamines, punishment for driving under the influence, and neutral arbitration on appeals.

But NFL spokesman Greg Aiello said in an email to The Associated Press: “There are unresolved issues. More negotiation ahead.”

Aiello did not specify which issues are not resolved, but called them “significant.”

Testing for human growth hormone was originally agreed upon in 2011, but the players have balked at the science in the testing and the appeals process for positive tests. If the proposal they voted on Friday is put into action, testing would begin for this season.

The player reps also approved an increase for the threshold for positive marijuana tests. Some players have complained that the NFL threshold of 15 nanograms per milliliter is so low that anyone within the vicinity of people smoking marijuana could test positive. The threshold was increased to 35 ng/ml in the league’s proposal.

Overall changes are retroactive for players suspended under previous policies, as well as for those in the appeal process. Those players, including Browns receiver Josh Gordon (suspended for the season) and Broncos receiver Wes Welker (four games), are subject to standards of the new policies. Their suspensions could be reduced — no immediate announcements were made regarding those suspensions, probably because the NFL doesn’t consider anything official yet.

Welker was suspended for amphetamine use in the offseason, but punishment for that is being switched from the performance enhancers policy to the substance abuse program — except for in-season violations.

A two-game suspension would be issued for a player convicted of driving under the influence. But an NFL proposal to immediately suspend a player, owner, coach, team executive or league employee for a DUI arrest was rejected by the union.

The players approved arbitration for appeals under the substance abuse and the PED policies. The NFL and NFL Players Association would hire between three and five arbitrators.

The league and the union also would retain independent investigators to review cases in which player confidentiality under the drug policy had been breached. Punishment for leaks could range up to $500,000 and/or termination of a job.

“This is an historic moment for our players and our league,” NFLPA President Eric Winston said long before the NFL basically put matters on hold. “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.”