UFC 183: Silva vs. Diaz was a mixed martial arts event held on January 31, 2015, at MGM Grand Garden Arena in Las Vegas, Nevada.

[3] A flyweight bout between Ian McCall and John Lineker was originally booked for UFC Fight Night: Shogun vs. St. Preux.

[4] A middleweight bout between Ed Herman and Derek Brunson was originally booked for UFC on Fox: dos Santos vs. Miocic.

The results came in on the day of the announcement and revealed Silva failed a drug test for drostanolone metabolites, which is an anabolic steroid.

[10] On the other hand, Nick Diaz had an amount of marijuana metabolites over the allowable limit in his post-fight test.

[11] NSAC chairman Francisco Aguilar confirmed that the fight had not yet been overturned and couldn't be until a motion was passed by a majority of the commission.

The commission rejected the defense and suspended him for one year retroactive to the date of the fight, as the current guidelines were not in effect at the time of the failed tests.

[22] ^ Kelvin Gastelum was fined 30 percent of his purse ($9,000) for failing to make the required weight for his fight with Tyron Woodley.

^^ John Lineker was fined 30 percent of his purse ($6,300) for failing to make the required weight for his fight with Ian McCall.