An inside source told ESPN.com on Tuesday that the NFL is in the process of renegotiating its drug policy and may institute changes specific to how athletes who use marijuana are handled. Since 2011, the NFL has been internally debating its drug policy, which includes testing for human growth hormones. If the current revisions to the drug policy are approved, the threshold for a positive marijuana test will be significantly increased, and punishments for violating the policy will be reduced. The…