Joe RiggsJoe Riggs has been forced to withdraw from his rematch with Nick Diaz after suffering a “bad reaction to an as of yet undisclosed drug,” according to GracieMag.com.

The bout for the newly-created Strikeforce Welterweight Championship was set to be featured on the Showtime-broadcast of Strikeforce’s August 15 event, which takes place at the HP Pavilion in San Jose, California. Diaz will reportedly remain on the card, taking on an opponent to-be-named, which is expected to be announced soon.

When welterweights Nick Diaz and Joe Riggs square off in a rematch at Strikeforce’s August 15 event the promotion’s newly-created 170-pound title will be on the line, according to MMA Weekly.

The Showtime-televised event, which takes place at the HP Pavilion in San Jose, California, features three other title bouts as Gina Carano and Cristiane “Cyborg” Santos meet for the Strikeforce 145-pound Women’s Championship, heavyweight champ Alistair Overeem takes on Fabricio Werdum, and lightweight champions Josh Thomson and Gilbert Melendez unify their titles.

Nick Diaz and Joe Riggs are likely to square off in a welterweight bout on the Showtime-televised main card at Strikeforce: Carano vs. Cyborg on August 15 in San Jose.

Though not yet signed, the bout is reportedly in the works for the event and both fighters are expected to agree to the rematch of their early-2006 meeting at UFC 57 which was won by Riggs via unanimous decision.

Jake Shields needed less than half a round to submit Robbie Lawler in the main event of Strikeforce: Lawler vs. Shields on Saturday, forcing Lawler to tap to a guillotine choke 2:02 into the opening round of their catchweight headliner. In other main card action, Brett Rogers knocked out Andrei Arlovski in just 22-seconds and Nick Diaz submitted Scott Smith.

The Strikeforce: Lawler vs. Shields preliminary card is scheduled to begin at 7:45pm ET with the main card, featuring Lawler-Shields and Arlovski-Rogers, commencing at 10pm ET. Live results are available after the jump...

All twenty-two fighters scheduled to fight at Saturday's Strikeforce event, including headliners Robbie Lawler and Scott Smith as well as main card fighters Andrei Arlovski, Brett Rogers, Nick Diaz, Scott Smith, Phil Baroni, Joe Riggs, Kevin Randleman, and Mike Whitehead, successfully made weight at Friday's weigh-ins.

Welterweights Joe Riggs and Phil Baroni are likely to meet on Strikeforce's rumored June 6th event in St. Louis. Both fighters have reportedly been offered the matchup but neither has officially signed on for the bout.

Kevin Randleman has signed with Strikeforce, Showtime has announced the Strikeforce broadcast team, Joe Riggs and Brett Rogers are under consideration to complete the April 11th main card, plus quotes and photos from Strikeforce's Thursday press conference.

Ever since ProElite closed its doors in October, there have been a lot of people expressing their hopes that Jake Shields would be able to make the move to the UFC. It looks like they will have to wait a bit longer to see if that possibility will ever become a reality. Yesterday [...]

Strikeforce today announced that Strikeforce light heavyweight champion Bobby Southworth will put his 205-pound title on the line against Renato “Babalu” Sobral in the main event of Strikeforce “Destruction” at the HP Pavilion in San Jose on November 21st.
“Babalu’s a tough fighter. He matches up well with anybody because he’s strong in every area,” [...]

Kazuo Misaki def. Joe Riggs via TKO (strikes) – Round 2, 2:29
Josh Thomson def. Ashe Bowman via TKO (strikes) – Round 1, 1:14
Terry Martin def. Cory Devela via TKO (strikes) – Round 3, 2:08
Mitsuhiro Ishida def. Justin Wilcox via submission (armbar) – Round1, 1:21
Trevor Prangley def. Anthony Ruiz via unanimous decision (29-28, 30-27, 30-26)
Luke [...]

Kazuo Misaki (185) vs. Joe Riggs (181.5)
Ashe Bowman (154.5) vs. Josh Thomson (155.5)
Mitsuhiro Ishida (156) vs. Justin Wilcox (155)
Cory Devela (185.5) vs. Terry Martin (185.5)
Trevor Prangley (203) vs. Anthony Ruiz (204)
Jesse Juarez (171) vs. Luke Stewart (169.5)
Eric Lawson (184.5) vs. Kenneth Seegrist (183)
Brandon Magana (172) vs. Brandon Thatch (170.5)
Jesse Gillespie (194) vs. Dave Martin [...]

Former Pride Fighting Championship Grand Prix winner, Kazuo “Grabaka Hitman” Misaki (22-8-1) will take on fellow middleweight wonder Joe “Diesel” Riggs (28-10) at Strikeforce mixed martial arts’(MMA) highly-anticipated return to the world-famous Playboy Mansion in Beverly Hills, Calif. on Saturday, September 20th.
“I am looking forward to making my debut for Strikeforce at The Playboy Mansion, [...]

– Mauricio “Shogun” Rua and former UFC light heavyweight champion Quinton “Rampage” Jackson are likely to rematch at the UFC’s year-end pay-per-view event on December 27th in Las Vegas. In their first meeting Rua defeated Jackson via first-round KO at PRIDE Total Elimination 2005 in April 2005.
– Georges St-Pierre and Jon Fitch were each awarded [...]

Kimbo Slice and Gina Carano will return to network television at EliteXC Saturday Night Fights 3 on October 4th at the Bank Atlantic Center in Ft. Lauderdale, Florida. The event will be broadcast on CBS. Carano will likely meet Cristiane “Cyborg” Santos at the event, while Kimbo may take on Brett Rogers, though several other [...]