Former UFC Heavyweight Champion Josh Barnett submitted a "positive test" prior to his much anticipated title fight against Fedor Emelianenko at Affliction: "Trilogy" from the Honda Center in Anaheim, Calif., on Aug. 1, according to Sherdog.com.

***UPDATE: Affliction Vice President Tom Atencio has confirmed with MMA Fanhouse that the August 1 main event between Fedor Emelianenko and Josh Barnett has been canceled.

Here's a snip:

"(Barnett) tested positive for a banned substance. The athletic commission will not reinstate his license. Him and Fedor is off."

Middleweight Vitor Belfort, a former light heavyweight who is already booked to fight Jorge Santiago in a 185-pound contest on the same night, has reportedly agreed to step in if needed; however, Atencio refused to comment on that possible scenario, as well as a potential call up for Bobby Lashley.

The California State Athletic Commission (CSAC) will apparently issue a "comprehensive statement" on its findings later today.

Stay dialed in to MMAmania.com throughout the day for more on this developing story.