SAN JOSE, Calif. -- Championship fights in Strikeforce's welterweight and middleweight divisions became official Friday, when Nick Diaz, Evangelista "Cyborg" Santos, Ronaldo "Jacare" Souza and Robbie Lawler made their contracted weight.
The evening's main event at HP Pavilion features a 170-pound affair between Diaz, attempting his second title defense, against the well-traveled Santos. Both fighters stepped on the scale at 169.5 pounds.
"I feel good and I'm ready to fight," Diaz said Thursday during the event's final press conference. "Cyborg has a unique style and I know that he will give it his all and be as crazy as ever. But that's good because I'm crazy, too."
Diaz (23-7) last fought to a five-round decision win over K.J. Noons in the same venue last October. Santos (18-13) was awarded the title shot despite having one welterweight title fight, a win last June against Dream champion Marius Zaromskis.
The middleweight championship pits well-respected fighters possessing divergent strengths. Souza (13-2), a five-time Brazilian jiu-jitsu world champion, will need to avoid Lawler's powerful strikes if he hopes to maintain the title, which was captured last August with a unanimous decision victory over Tim Kennedy.
"Some were surprised that I stood last time but Lawler is a different kind of fighter than I had in my last one," said Souza, 184.25 pounds. "If I have to stand, I will, of course, but I know it is important that I keep control."
Lawler (18-6) weighed in at 184 pounds.
Also on the card, former football star Herschel Walker (1-0) makes his second appearance in a cage, talking on Scott Carson (4-1), who appeared much larger than the 214 pounds he was said to have weighed. Walker, trim and fit a the age of 48, weighed 220.25 pounds.
The evening's first televised fight (Showtime, 10 p.m. ET), pits Brazilian jiu-jitsu masterRoger Gracie (206) against veteran Trevor Prangley (205.25). The bout mark's the first for Gracie (3-0) since May of 2010. He said he expects to commit himself to mixed martial arts this year, and fight up to three times. Prangley (23-6-1) should be the stiffest test of Gracie's short career.
Undercard fighters Nathan Coy and Jenna Castillo came in overweight.
Nick Diaz, 169.5; Evangelista Santos, 169.5
Ronaldo Souza, 184.25; Robbie Lawler, 184
Herschel Walker, 220.75; Scott Carson, 214
Roger Gracie, 206; Trevor Prangley 205.25
Nate Moore, 171; Nathan Coy, 171.25* (Limit 171)
Bobby Stack,154.75; Isaiah Hill, 155.5
Ron Keslar, 179.5; Eric Lawson, 180
Germaine de Randamie, 135.5; Stephanie Webber, 135.75
Lucas Gamaza, 171; James Terry, 170.5
Charlene Gellner, 118; Jenna Castillo 121.5** (Limit 121 lbs)
Josh Gross covers mixed martial arts for ESPN.com.