Japanese mixed martial arts promotion RIZIN FF will host a 16-man openweight tournament starting Sept. 25 in Tokyo, and two formerly retired legends are scheduled to compete, an official told ESPN.

Former PRIDE Grand Prix champion Mirko "Cro Cop" Filipovic and former PRIDE middleweight champion Wanderlei Silva have both agreed to participate in the tournament, the official said.

The tournament will take place over the course of three dates: Sept. 25, Dec. 29 and Dec. 31. The rest of the field is expected to be announced soon.

Mirko "Cro Cop" Filipovic is still serving a two-year drug suspension from the UFC, but the suspension does not prohibit him from fighting in a RIZIN competition in Japan. Ed Mulholland

Filipovic (31-11-2) is still serving a two-year suspension after admitting he used human growth hormone to the United States Anti-Doping Agency in November 2015. The suspension applies to Filipovic's career in the UFC, the promotion for which he was competing at the time his sanction began.

That suspension prohibits him from fighting in the UFC, but not from a RIZIN competition in Japan. According to RIZIN officials, Filipovic secured his contractual release from the UFC in order to participate in the tournament. On Friday, UFC officials did not respond to a request for confirmation.

Silva (35-12-1), 40, will be one of four tournament participants to receive a bye in the opening round. He successfully negotiated his release from the UFC in January.