The event is scheduled to take place at the HP Pavillion in San Jose, California.
Sources within Strikeforce recently confirmed the bout according to a recent report on Carson’s Corner.
This bout between the two will be the second professional mixed martial arts match-up but their third fight as the two traded blows in the hospital following their first encounter.
Riggs won the previous match-up between the two at UFC 57 as he edged out Diaz in a hard fought unanimous decision victory.
Diaz last saw action on May 6 where he submitted Scott Smith with a rear naked choke in the third round of “Strikeforce: Lawler vs. Shields”,the same card where Riggs bested Phil Baroni by unanimous decision in his last outing.