Brett Okamoto breaks down the details of Nick Diaz's provisional suspension, how long of a suspension he is facing and the steps he can take to counter the measure. (1:17)

UFC welterweight Nick Diaz is facing a potentially lengthy suspension for a possible anti-doping violation, the promotion announced on Thursday.

Diaz (26-9) has been provisionally suspended by the United States Anti-Doping Agency (USADA) for failing to disclose his whereabouts multiple times within the past 12 months.

Under the UFC's anti-doping policy, which is overseen by USADA, all athletes are required to inform the agency of their whereabouts to ensure the possibility of out-of-competition testing.

Any athlete who fails to do so three or more times in a 12-month period is subject to a suspension ranging anywhere from six months to two years.

"USADA, the independent administrator of the UFC Anti-Doping Policy, will handle the results management and appropriate adjudication of Diaz's case, who has been provisionally suspended pending the final resolution of this matter," the UFC stated.

Diaz, 33, hasn't fought since he suffered a decision loss to Anderson Silva at UFC 183 in January 2015. That result was later changed to a no-contest, after Silva tested positive for multiple banned substances.

Diaz also failed a post-fight drug test at UFC 183 for marijuana metabolites. It was the third marijuana-related failed drug test of Diaz's career. He was initially suspended for five years, but that was later reduced to 18 months.

Fighting out of Stockton, California, Diaz is one of the most popular fighters in the UFC. He has the right to a hearing, regarding this potential anti-doping violation.

UFC president Dana White recently told MMAJunkie.com he did not think Diaz would ever fight again.