A potentially torn ACL and meniscus will prevent Strikeforce Light Heavyweight (205 lb. limit) Champion Bobby Southworth from being able to defend his crown against Renato “Babalu” Sobral (30-7) at the world-famous Playboy Mansion in Beverly Hills, California on Saturday, September 20th. Replacing the ailing Southworth in the fight with Sobral will be Anthony “A-Train” Ruiz (21-11).

The 38-year-old Southworth sustained the knee injury during a routine training session at American Kickboxing Academy (AKA) in San Jose. A physician, who pinpointed the affected areas, has ordered Southworth to undergo an MRI exam to determine the extent of the damage and to go through four to six weeks of physical therapy.

Ruiz, a 30-year-old resident of Modesto, California, is coming off a July 26th unanimous judges’ decision victory over Jeremy Freitag.

Ruiz holds a 1-1 record against Southworth. After their initial meeting, a non-title bout on November 16, 2007, was stopped 52 seconds into the second round due to a cut Ruiz had opened around Southworth’s eye, Ruiz was awarded a win by TKO.

Southworth avenged the loss by legging out a five-round, unanimous judges’ decision over Ruiz at San Jose’s HP Pavilion on June 27th.

“Strikeforce At The Mansion II” will be highlighted by a showdown between 2006 Pride Fighting Championship Grand Prix winner and world top 10 ranked, Kazuo “Grabaka Hitman” Misaki (20-8-2), and 25-year-old former UFC star, Joe “Diesel “Riggs (28-10).

Twenty-four year old thoroughbred Cory “The One” Devela (9-1) will bid for his eighth consecutive victory when he takes on what is arguably his most dangerous challenge to date, heavy-handed Terry Martin (17-5), in a middleweight (185 lb. limit) contest

Newly crowned Strikeforce World Lightweight (155 lb. limit) Champion Josh “The Punk” Thomson (16-2) will also return to action in a three-round, non-title matchup with Lion’s Den prodigy Ashe Bowman (10-4).