Conor McGregor is NOT currently receiving treatment for substance abuse, despite Chael Sonnen suggesting otherwise ... 'cause a rep for the UFC superstar tells TMZ Sports he's not in rehab.
The American Gangster dropped the bombshell allegation on his "Good Guy/Bad Guy" show with Daniel Cormier on Monday ... calling B.S. on Conor's claim that an injury forced him to back out of his fight against Michael Chandler.
The two hosts were discussing how both Conor and Michael have a history of promoting alcohol products .