HOLLYWOOD, Calif. -- Former EliteXC champions Jake Shields and Robbie Lawler will face off in a non-title middleweight contest for Strikeforce in May at a yet-to-be-announced Washington state venue. Shields will take the leap to middleweight to face the Iowa striker, said Strikeforce CEO Scott Coker at a press conference on Thursday.

The 30-year-old Brazilian jiu-jitsu black belt had been previously announced to square off against power puncher Joe Riggs at Strikeforce’s April 11 event in San Jose, Calif. That bout is now on hold, said Strikeforce representatives.

Shields was the EliteXC 170-pound champion prior to parent company Pro Elite’s financial collapse. Shields, along with Lawler, were among 42 fighters whose contracts were purchased by Strikeforce in a select assets acquisition deal finalized in February.

The top-10 ranked Shields went 4-0 for the EliteXC promotion. His last victory, a second-round armbar submission against brawling Brit Paul Daley, was televised on CBS last October. Shields (24-2-1) boasts wins over UFC middleweight contender Yushin Okami, as well as welterweight standouts Mike Pyle, Nick Thompson, and former WEC champion Carlos Condit.

A hot prospect from the start, the hard-nosed Lawler landed in the UFC by his fifth career fight. He fought for the promotion seven times as a welterweight between 2002-2004, and collected victories over Chris Lytle and Aaron Riley before losing to Nick Diaz by knockout and the late Evan Tanner from a triangle choke.

The Iowa native flourished outside the Octagon’s gates thereafter, racking up two key victories in Hawaii’s Icon Sport before gaining national exposure on two of EliteXC’s three “Saturday Night Fight” installments on CBS, which netted over 8 million viewers for Lawler’s fights alone.

A product of the famed Miletich Martial Arts camp, Lawler (16-4) currently trains with former UFC welterweight champion Matt Hughes at his H.I.T. Squad gym in Granite City, Ill.

Strikeforce’s May event will air live on Showtime.