If Conor McGregor truly plans on retiring, it would set off a domino effect beyond just a change in the main event of UFC 200.

There would be a new featherweight champion, of course. UFC president Dana White has already indicated that should the reigning titleholder end his career, McGregor's belt will be vacate and awarded to the winner of the Frankie Edgar vs. Jose Aldo fight at UFC 200.

But there are also implications involving USADA's anti-doping testing that would potentially complicate McGregor's return.

According to USADA policy, McGregor most notify the UFC in writing of his retirement intentions. Up until that point, he is still subjected to USADA testing, and refusal to participate is a violation of policy.

In the event McGregor followed through on his threat to retire, and then later decided to return, he would be subjected to testing for a four-month period before he would once again be allowed to compete.

On Wednesday's edition of the FOX Sports 1 show UFC Tonight, White said he's yet to receive a formal retirement notice from McGregor.

"If Conor McGregor is truly retired, he would have to take four months off before, it would take you four months to come back, because of USADA. You can't just say, now that you have random drug testing, after however long you're out, just say ‘okay, now I'm back.'"