MMARising.com first reported the matchup on Monday.
The event takes place at the HP Pavilion in San Jose. It could feature two title fights; Nick Diaz is scheduled for the event, but doesn’t have an opponent, and middleweight champion Ronaldo “Jacare” Souza is scheduled to defend his title against Robbie Lawler.
Prangley last competed in September, defeating former UFC star Keith Jardine at Shark Fights 13. Prangley is the Shark Fights light heavyweight champion, while Jardine was attempting to rejuvenate his career after being cut by the UFC.
Gracie only has three fights in mixed martial arts, but won all three bouts by submission. He last competed in May, defeating Kevin Randleman by rear-naked choke.