Green has issued an explanation to the press: http://www.milehighreport.com/2012/3/9/2858539/d-j-williams-virgil-green-release-statements-accusation-of
Looks like the link doesn't work, here is his explanation:
Virgil Green also released a statement to Josina Anderson, and indicated that the positive result was not from a PED as implicated by the league, but an ADHD medication he took prior to getting an exemption from the league.
Green says he has since gotten the required exemption for the prescribed medication. I find it very surprising that such an infraction merited a 4 game suspension.
[ Edited by NV9erfan on Mar 10, 2012 at 3:21 PM ]