by MMAFighting www.mmafighting.com Joe Riggs (26-9) has left World Extreme Cagefighting (WEC) for the California-based Strikeforce. Strikeforce announced today that the 24-year-old middleweight will make his company debut on September 9 at "Strikeforce at the Mansion" in Beverly Hills, California. His opponent will be 41-year-old Eugene Jackson (15-7-1), a 7-time UFC veteran who rejuvenated his career last year with Strikeforce by staying undefeated through three bouts. Riggs recently requested and was granted a release by Zuffa from his 4-fight WEC contract. According to The Fight Network, Riggs' jump was driven by the pursuit of higher pay with the ability to compete less often.