While no official statement on whether Lesnar will ask for a B sample has been made - judging by Brock Lesnar's response to news that he failed a USADA drugs test ahead of UFC 200 - he looks like he will be fighting to clear his name.
Lesnar responded to the result by providing the Associated Press with copies confirming he had passed his previous drugs tests since his announcing his UFC return and provided a seven word statement:
We'll get to the bottom of this.
Lesnar was given an exemption by USADA in order to fight at UFC 200, because he didn't announce his return to the sport giving USADA a four month notice for drug testing.
USADA have issued a statement to Fox Sports, following Lesnar's response:
With Mr. Lesnar having spoken publicly about the issue, I can confirm that he has been notified of a potential anti-doping policy violation stemming from an out-of-competition sample collection on June 28, 2016.
can also confirm that the results from his previous samples collected by USADA were all reported as negative. Although USADA will not be providing any further specifics of the case at this time, I can tell you that Mr. Lesnar — as with every athlete under the UFC anti-doping policy — will be provided full due process under the rules.
The next step will be presumably that Lesnar will have the B sample tested. You'd have to think that from his initial response, he'll be looking to fight any sanction that he will receive.
[Fox Sports]