The event was originally supposed to be headlined by McGregor challenging Rafael dos Anjos for the UFC Lightweight Championship, but the Brazilian was forced to withdraw from the bout after suffering a broken foot in training, per Ariel Helwani of MMAFighting.com.
Given the last-minute adjustment as well as the uncertainty surrounding Diaz, it should come as no surprise that McGregor will enter the March 5 showdown in Las Vegas as a heavy favorite.
Source: Odds Shark
During a Tuesday night appearance on SportsCenter (via Brett Okamoto of ESPN.com), White said the UFC made calls to multiple fighters to take Dos Anjos' spot: "We called Jose Aldo; Jose Aldo turned the fight down. We called Frankie Edgar; Frankie Edgar turned the fight down. Those are two guys everybody was talking about."
It's not a surprise that Aldo and Edgar turned down the opportunity to fight McGregor. They don't have the time to prepare for a high-profile bout, and Aldo is smart enough to know a second fight with McGregor will require him to be 100 percent after the Irishman knocked him out in 13 seconds in December.
Diaz, who has only been out of the Octagon for two months since his win over Michael Johnson, has an opportunity to keep momentum going.
The 30-year-old had a disastrous run before defeating Johnson, missing weight in his December 2014 bout against Dos Anjos and losing via unanimous decision. It took him 12 months to step back into the cage following that defeat.
McGregor is taking a chance with this bout by moving up two weight classes from his usual featherweight to welterweight on short notice. He hasn't been shy about his willingness to fight anyone in any weight class:
Yet this is McGregor's first bout at 170 pounds in the UFC. He's certainly proved to be a powerful striker, owning 17 knockouts among his 20 career victories, but this is uncharted territory for The Notorious.
Diaz's desire is always a question, as he missed weight against Dos Anjos by more than five pounds and didn't bother to try cutting to avoid a financial penalty.
McGregor is operating at such a high level and was already preparing for one of the best fighters in the world, so he should have no problems stopping Diaz at UFC 196.