TJ Dillashaw relinquished his UFC bantamweight title after an "adverse finding" in a test for his Jan. 19 fight in Brooklyn, he wrote in a post on his Instagram account Wednesday morning.
He also was suspended one year, retroactive to Jan. 19, 2019, and fined $10,000 by the New York State Athletic Commission for violations relating to use of a prohibited substance.
A UFC official confirmed Dillashaw has vacated the title.
"To all my fans, I wanted to be the first one to let you know that USADA and the NYSAC have informed me of an adverse finding in a test taken for my last fight," Dillashaw wrote. "While words can't even begin to express how disappointed I am at this time, please know that I'm working with my team to understand what has occurred and how to resolve this situation as quickly as possible. Out of fairness and respect to the rest of my division, I've informed the UFC that I'll be voluntarily relinquishing my title while I deal with this matter. I want to thank all of you in advance for the support."
According to the USADA's UFC athlete testing website, Dillashaw, 33, has been tested twice this year.
"In light of Mr. Dillashaw's social media post this morning, we can confirm that an in-competition test conducted by USADA on January 18, 2019 resulted in an adverse analytical finding," USADA said in a statement Wednesday afternoon. "In this instance, we are able to confirm the finding due to Mr. Dillashaw's public statement. The presumption of innocence under the rules is a vital part of an effective anti-doping program and it's only fair that Mr. Dillashaw be allowed due process before any conclusions are drawn."
What has not been made public by Dillashaw, USADA, NYSAC or the UFC is what Dillashaw tested positive for in his in-competition test the day before the fight.
Dillashaw (16-4) challenged flyweight champion Henry Cejudo for his title at the Barclays Center, losing via first-round TKO. He was attempting to become the first UFC fighter to drop down in weight to claim a second simultaneous title.
Dillashaw relinquishing the title opens the division to several possibilities for its next champion. There had been talk of Cejudo moving up to challenge Dillashaw for his title, but with Dillashaw no longer the champion, that bout loses its story line and likely much fan interest.
Marlon Moraes is the No. 1 contender with four straight wins, including three by first-round knockout. Raphael Assuncao is ranked No. 2, but he and Moraes already have fought twice, including last month. Uniondale's Aljamain Sterling is No. 3 and has won three straight. His last loss was via first-round knockout to Moraes in December 2017.