Former UFC lightweight title challenger Nate Diaz took a page out of his older brother’s playbook on Wednesday when he no-showed the UFC on FOX 13 open workouts.

MMA Fighting first reported the news, noting that Diaz was the only one of the top four fighters on the card who didn’t participate in the event at Phoenix’s U.S. Airways Center.

Event headliners Junior dos Santos, Stipe Miocic, as well as Rafael dos Anjos – Diaz’s opponent, all attended the media/fan friendly event.

According to the report, UFC officials did not give a reason as to why Diaz did not attend the regularly scheduled fight week event.

Diaz hasn’t fought in 13 months, scoring a decisive win over fellow ex-title challenger Gray Maynard in November of last year.

The Cesar Gracie Brazilian jiu-jitsu black belt was removed from the UFC’s rankings in May and has been in a public feud with the company due to a contract dispute.

Despite not receiving a more lucrative deal, Diaz decided to return from his self-imposed hiatus in September when he signed on for a matchup with dos Anjos.

While Diaz is 4-2 in his past six matchups, he is just 1-2 in his past three contests and suffered the first knockout loss of his career against Josh Thomson at UFC on FOX 7 in April.

Meanwhile, his Brazilian counterpart is 2-1 in his last three bouts and has been victorious in eight of his past nine fights, calling for a title shot if he defeats Diaz on Saturday night.