Former UFC lightweight title contender Joe Stevenson (31-11) has been forced to withdraw from his main card bout against Takanori Gomi (31-6) at UFC on Versus 2 in August after suffering a knee injury in training.

Stepping in to replace Stevenson against the former Pride lightweight champion will be Tyson Griffin (14-3), according to noted MMA insider Dave Meltzer.

It is very unfortunate for Stevenson, as a win over a big name fighter like Gomi would have gotten his career headed back in the right direction. "The Ultimate Fighter" season 2 winner has gone 2-3 in his last five bouts, suffering losses to Kenny Florian, Diego Sanchez and most recently George Sotiropoulos at UFC 110 in February.

Griffin is fresh off a loss against former training partner Evan Dunham at UFC 115 on June 12. Prior to the loss, he posted back-to-back wins over Rafael dos Anjos and Hermes Franca.

The Xtreme Couture product has put together a 7-3 UFC record since debuting with the promotion in Sept. 2006, scoring other notable Octagon wins over Clay Guida, Thiago Tavares, Gleison Tibau and Marcus Aurelio. His only other UFC losses have came against former UFC lightweight champion Sean Sherk and current UFC 155-lb champ Frankie Edgar.

Gomi most recently suffered a loss in his UFC debut, as he was defeated by Kenny Florian in the main event of UFC Fight Night 21 in March. The loss snapped Gomi's two-fight winning streak, as he previously defeated Takashi Nakakura and Tony Hervey prior to joining the UFC.

Gomi is most known for his successful run in the now-defunct Pride organization (February 2004 to February 2007), where he was considered to be one of the best lightweights in the world. He put together a superb 13-1 (1 NC) record with Pride, scoring big wins over Jens Pulver, Luiz Azeredo (x2), Tatsuya Kawajiri, Hayato Sakurai and Mitsuhiro Ishida.

UFC on Versus 2 takes place on August 1 at the San Diego Sports Arena in San Diego, California. The event is headlined by a light-heavyweight bout between fast-rising phenom Jon Jones and 12-year veteran Vladimir Matyushenko.

In addition, rising middleweight contenders Yushin Okami and Mark Munoz will look to climb further into contention when they battle it out in the night's co-main event. A welterweight bout between prospects John Howard and Jake Ellenberger will also be featured on the main card.