Strikeforce “Carano vs Cyborg” began with a whopping four title bouts, but now only two are left.

GracieFighter.com, the official website of Nick Diaz’s camp, is reporting that Diaz’s scheduled opponent Joe Riggs has pulled out of the vacant welterweight title bout due to a bad reaction to an undisclosed drug.

The two would have fought in a rematch from a February 2006 fight at UFC 57 that saw Riggs walking off with a unanimous decision after three rounds. But the fight didn’t stop there, Diaz and Riggs almost went at it in the hospital after the fight.

Diaz will remain on the card against an opponent to be announced.

FULL CREDIT: MMAFIGHTING.COM