UFC officials made the announcement earlier today.
Castillo made his UFC debut at “UFC on Versus 3” last March against Joe Stevenson, earning a unanimous decision victory and extending his winning streak to three in a row. Prior to that contest, he defeated Will Kerr and Dustin Poirier in his final two WEC bouts.
Meanwhile, Volkmann has made news both in and out of the cage. Following his victory over Antonio McKee at UFC 125 last January, he made comments regarding President Barack Obama, stating that he would like to fight the commander-in-chief. The remarks stirred up a bit of controversy, though ultimately did not cause the fighter any problems.
The lightweight contest will likely end up on the preliminary card of “UFC on Versus 5” on August 14 in Milwaukee, Wisconsin. The event will feature a welterweight contest between Dan Hardy and Chris Lytle, along with a lightweight bout between Ben Henderson and Jim Miller.
