Not sure if there is anything behind this at all but it was brought to my attention by @MookieAlexander, a writer for Bloody Elbow who quoted it on twitter. Could be nothing but just thought I'd let you guys know that there is a rumor going around. Have at it.
EDIT: Sorry guys, I'm not too up to date on drug testing policies. But for those wondering whether this would have him out of the Holloway fight, it looks like not due to the fact that it's out of competition. Similar to the Jones situation when he tested positive. Thanks to those who explained this in the thread.