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.'”