Former Washington state Sen. Dino Rossi (R) will announce his challenge to Sen. Patty Murray (D) on Wednesday, GOP sources confirmed Monday afternoon.

The recruitment of Rossi, a two-time gubernatorial nominee, comes as a victory for the National Republican Senatorial Committee. National Republicans have been wooing him for months as the contest has filled up with a crowd of little-known GOP candidates. Early polling has shown that a Murray/Rossi race would be highly competitive.

But Rossi will have to work quickly to collect enough money to secure the nomination in August and to compete with Murray, who had nearly $6 million in the bank at the end of March.

Also standing in his way will be the Democratic Senatorial Campaign Committee, which has been taking shots at the former state Senator since his name first emerged for the Senate contest earlier this year.

DSCC spokesman Eric Schultz was quick to paint the GOP primary as a fight between the party’s extreme elements and the establishment, pointing to former Alaska Gov. Sarah Palin’s endorsement last week of tea party candidate Clint Didier (R).

“With other Republican establishment candidates continuing to lose to the extremists in their states, we know that Dino Rossi has his work cut out for him, especially considering his history of shady deals, questionable business arrangements, and other ethical lapses,” Schultz said.