Strikeforce welterweight champion Nick Diaz (23-7, 1 NC) will make his second title defense when he faces Brazilian powerhouse Evangelista Cyborg (18-13) in main event action and Strikeforce middleweight (185 pounds) champion "Jacare" Souza (13-2, 1 NC) will put his belt on the line for the first time when he squares off with power-punching knockout artist "Ruthless" Robbie Lawler (18-6, 1 NC) in the co-main event of a stacked MMA fight card at HP Pavilion in San Jose, Calif.

In other action, football legend and MMA upstart, Herschel Walker (1-0) will return to the cage to face Scott Carson (4-1) in a heavyweight bout. The latest prospect from MMA's first family, undefeated Roger Gracie (3-0), will battle former South African national wrestling champion and MMA star Trevor Prangley (23-6-1) at light heavyweight (205 pounds).

The 27-year-old Diaz has been unstoppable of late, winning his last eight fights. In his latest effort, the 6-foot-1 Brazilian Jiu-Jitsu black belt and potent striker settled a three-year old score with arch-nemesis K.J. Noons, out-striking Noons en route to a five-round unanimous decision at HP Pavilion last Oct. 9.

Five months prior to the victory over Noons, the no-nonsense Diaz, ventured to Saitama, Japan, to face top-ranked rival Hayato "Mach" Sakurai in a DREAM promoted affair. To the surprise of many, the southpaw Diaz made quick work of Sakurai, submitting the Japanese fighter with an armbar at the 3:54 mark of the first round.

Like Diaz, Cyborg, husband of Strikeforce Women's middleweight champion Cris Cyborg, possesses tremendous striking abilities, having KO'd 11 of his 18 victims. In his last outing, the 5-foot-10 Cyborg, who hails from Rondonopolis, Brazil, scored a first-round TKO (punches) over highly-touted Marius "The Whitemare" Zaromskis at Strikeforce: Live at Nokia Theatre in Los Angeles last June 16.

Prior to defeating Zaromskis, Cyborg scored a first-round TKO on Daniel Zarate with a head kick and flurry of punches in Curitiba, Brazil on Dec. 12, 2009.

Souza, a Brazilian Jiu-Jitsu black belt, captured the vacant Strikeforce middleweight crown last Aug. 21 when he earned a hard-fought unanimous decision over American military hero Tim Kennedy at Toyota Center in Houston, Tex. A slick submission specialist who has tapped out 10 of his 13 victims, the 6-foot Souza surprisingly opted to stand and exchange punches and kicks with his opponent for five rounds rather than take the fight to the mat.

A resident of Rio de Janeiro, Brazil, Souza, who celebrated his 31st birthday on Dec. 7, earned a crack at the middleweight title by winning his first two Strikforce fights. In his debut on Dec. 19, 2009, he submitted 1996 Olympic wrestling silver medalist Matt Lindland with an arm triangle choke at the 4:18 mark of the first round. Last May 15, Souza earned a unanimous decision over Joey Villasenor at Scottrade Center in St. Louis.

Souza's only losses came in his first career match in 2003 and then to Gegard Mousasi at the DREAM 6: Middleweight Grand-Prix Final in Saitama, Japan, in 2008. The showdown with Mousasi came shortly after Souza had claimed victory earlier on the same night over Zelg Galesic with an armbar submission in the first round of a quarterfinal round tournament bout.

Over the course of the 2008 DREAM tournament series, Souza also triumphed over Ian Murphy with a first-round (3:38) rear naked choke and over superstar Jason "Mayhem" Miller via unanimous decision.

The 28-year-old Lawler's title shot...