Brock Lesnar’s upcoming return to MMA after an absence of four and a half years normally would have required four months advance notice to the UFC before he could be placed on a card.

But Lesnar’s return from retirement came under special enough of a circumstance that he was able to avoid that stipulation, part of the UFC’s Anti-Doping Policy rules, and was granted an exemption from the four-month notice policy, according to Yahoo! Sports‘ Kevin Iole.

This past Saturday during the UFC 199 pay-per-view broadcast, it was announced that Lesnar (5-3 MMA, 4-3 UFC) will fight in the UFC 200 heavyweight co-main event in July. On Monday, it was announced his opponent will be Mark Hunt (12-10-1 MMA, 7-4-1 UFC). UFC 200 takes place July 9 at T-Mobile Arena in Las Vegas and airs on pay-per-view following prelims on FOX Sports 1 and UFC Fight Pass.

According to Rule 5.7.1 of the UFC’s Anti-Doping Policy, fighters coming out of retirement have to give the promotion a four-month heads up that they plan to return to the octagon. And that period is used to put that fighter into the pool for random out-of-competition drug testing.

However, according to the rule, an exemption may be given, at the UFC’s discretion, “in exceptional circumstances or where the strict application of that rule would be manifestly unfair to an Athlete.”

That will be the case for Lesnar, who most recently fought in late December 2011 in a title eliminator against Alistair Overeem, who stopped him with a first-round TKO.

In a statement to Yahoo! Sports, the UFC said Lesnar’s length of time away from the promotion, as well as the fact he only signed a deal to fight at UFC 200 this past Friday, a day before his return was announced, were contributing factors in waiving the four-month notice rule.

“Given Lesnar last competed in UFC on December 30, 2011, long before the UFC Anti-Doping Policy went into effect, for purposes of the Anti-Doping Policy, he is being treated similarly to a new athlete coming into the organization,” the UFC’s statement to Yahoo! 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.”

Lesnar returns to the cage for the first time since his loss to Overeem, which concluded a four-year UFC run that included a two-year reign as heavyweight champion. Lesnar first joined the UFC in 2008 after a 2000 NCAA Division I national wrestling championship and a successful run as a WWE star.

The 38-year-old won the UFC belt with a 2008 win over Randy Couture and defended it with victories over Frank Mir and Shane Carwin. However, following subsequent defeats to Cain Velasquez and Alistair Overeem – and a lengthy battle with diverticulitis – Lesnar retired from the UFC and eventually returned to pro wrestling.

According to a WWE statement, Lesnar’s UFC 200 involvement is a “one-off opportunity” and doesn’t mark a full-time return to MMA.

For more on UFC 200, check out the UFC Rumors section of the site.