If you're a professional fighter coming out of retirement, you have to notify the UFC and its drug-testing partner, the United States Anti-Doping Agency, four months in advance.
Unless, that is, the UFC says you don't.
The WWE star's return was revealed on June 4, and according to an official UFC statement released to Kevin Iole of Yahoo Sports, he made himself available for USADA drug testing on June 6. That shaves about three months off the typical drug-testing window for an un-retiring UFC athlete.
In part, the UFC statement reads:
While conversations with the heavyweight have been ongoing for some time, Lesnar required permission from WWE to compete in UFC 200 and only agreed to terms and signed a bout agreement last Friday. He was therefore unable to officially start the Anti-Doping Policy process any earlier. UFC, however, did notify Lesnar in the early stages of discussions that if he were to sign with the UFC, he would be subject to all of the anti-doping rules. Lesnar and his management have now been formally educated by USADA on the policy, procedures and expectations.
The official UFC-USADA policy stipulates that "UFC may grant an exemption to the four-month written notice rule in exceptional circumstances or where the strict application of that rule would be manifestly unfair to an athlete."
According to a statement from the WWE, its multitime champ is still under contract with WWE but will return for a "one-off opportunity" at UFC 200. Lesnar (5-3), who won and twice defended the UFC heavyweight title between 2008 and 2010, will face knockout artist Mark Hunt at the event in Las Vegas.
Lesnar's original UFC run ended in late 2011 when he lost by knockout to Alistair Overeem.
Although he's best known for pro wrestling, Lesnar also has substantial amateur pedigree. The 38-year-old won a national title while wrestling for the University of Minnesota.