Japan Times (and a number of other media outlets) are reporting this today. We reported it back on October 8th. Do the math:

Judoka Satoshi Ishii, who won the men’s over 100-kg gold medal at this year’s Beijing Olympics, is to quit judo and become a professional mixed martial artist, judo sources said Friday.

The 21-year-old Ishii visited the All Japan Judo Federation on Friday to notify it of his decision and is expected to formally announce his switch to mixed martial arts at a news conference in Osaka on Monday, the sources said.

Ishii had been pondering the move and told Kazuo Yoshimura, chief technical director of the federation, earlier this month that he intends to quit judo.

He will become the third Olympic gold-medal winning judoka to switch to pro mixed martial arts after Hidehiko Yoshida, the 78-kg champ at the 1992 Barcelona Games, and Makoto Takimoto, who won the 81-kg title at the 2000 Sydney Olympics.

Ishii to switch to MMA @ Japan Times