One day after re-signing its world welterweight champion, Nick Diaz, to a new multi-fight deal, Strikeforce announced Wednesday that exciting, hard-hitting former two-time world middleweight champion "Ruthless'' Robbie Lawler had also signed a new, multi-year agreement with the San Jose, California based organization.

One of the most lethal punchers in his weight class, Lawler (18-6, 1 NC) will challenge Strikeforce middleweight belt-holder "Jacare" Souza (13-2, 1 NC) in one half of a Strikeforce championship doubleheader on Saturday, Jan. 29, at HP Pavilion in San Jose, Calif. Diaz (23-7, 1 NC) will defend his title against Brazilian powerhouse Evangelista Cyborg (18-13) in the other.

Lawler, a 5-foot-11, 28-year-old southpaw fan favorite from Granite City, Ill., is coming off one of the most devastating MMA knockouts of 2010 - a brutal, single-punch, 50-second annihilation of Matt Lindland last Dec. 4 at Scottrade Center in St. Louis. Fifteen of Lawler's 18 career victories have come via knockout or TKO.

"Strikeforce has treated me good and I am happy to re-sign with them," said Lawler. "They have given me an opportunity to fight for the title and I'm looking forward to that and to fighting any and all of the top 185-pounders.''

Since September 2006, Lawler has gone 7-2-1 with one no contest. Three fights ago, the athletic, aggressive crowd-pleaser registered a dramatic, come-from-behind first-round (3:33) KO over highly regarded Melvin Manhoef on Jan. 30, 2010.

Lawler, who turned pro at 19, fought Scott "Hands Of Steel'' Smith during the first-ever primetime network telecast of MMA on May 31, 2008, on The CBS Television Network.

In other featured action, football legend and MMA upstart, the incredible Herschel Walker (1-0) will return to the cage to face Scott Carson (4-1) in a heavyweight bout and 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).