The right back tested positive for a metabolite of cocaine following a Premiership match between Partick and Celtic on 3 December 2014.
McMillan, 27, from Glasgow, was initially banned for two years by the National Anti-Doping Panel (NADP) on 21 April 2015. Following an appeal by McMillan, the NADP re-convened in Glasgow on 21 July 2015, and upheld the original decision. As a result McMillan was banned from all competitive sport from 18 December 2014 to 17 December 2016.
But UK Anti-Doping (UKAD) has today confirmed that McMillan has had his suspension reduced by one month “for providing Substantial Assistance”.
A statement from UKAD said: “McMillan provided information to Police Scotland which the NADP concluded was sufficient to amount to Substantial Assistance, and so found that his sanction should be reduced by one month.”
It means the player’s ban will now expire on 17 November 2016.