That's the number Green has made famous while winning two NBA championships, but as a proud American he wanted to let McGregor know who he's riding with on August 27.
"We rocking with Floyd bro not you," Green wrote, in an Instagram post with a photograph of McGregor in the singlet. "Take that off bruh."
But the brash basketballer quickly learned who he was dealing with - and that it's important to do your research before taking on a man like McGregor.
You see, there's a reason the UFC superstar was wearing that specific jersey and it has nothing to do with the modern day Warriors or Green.
Before Green adopted the number made famous by Michael Jordan and LeBron James, a point guard named C.J. Watson wore it for Golden State.
He wasn't exactly a superstar, averaging just 10 points and three assists in his best season in the Bay Area, but that's not why McGregor wanted to recognise his work.
Nope, it's what Watson did off the court that "The Notorious" wanted to remind people of. A few years back, Watson was dragged into a domestic violence case involving Mayweather and his former partner when it was alleged the pound for pound champ was alleged to have punched her in front of their children after finding text messages from Watson on her phone.
Mayweather, despite spending two months in prison as a result of the charge, continues to deny and downplay the incident.
But that doesn't mean a master of mental warfare like McGregor isn't going to find ways to jab him about it. Hence the Watson jersey.
He made this emphatically clear to Green. "That's C.J. Watson mate," McGregor wrote, in reply to Green's post. "I don't know who the f*** you are. No disrespect tho kid, keep hustling and stay in school."
"Now ask yourself why I'm rocking C.J when I don't know or give a f*** about basketball," McGregor added. "I dribble heads off the floor. Not a ball. This is no game here kid."
Draymond tried to hit back: "Hahahahaha that number won't be worn again when I'm finished with it clown! Gold medalist, all star, DPOY etc!!! Hahaha stop it boy! Nate Diaz (Bay Area stand up) whooped you in your ring! Money May about to destroy you!!! Take that Warriors jersey off bruh you're an incredible internet troll we don't rock with you! Go train bum!!"
But the damage was done - this was a victory to McGregor.
