Rep. Shelley Moore Capito (R-W.Va.) will announce Monday that she will run for Senate in 2014, according to someone familiar with Capito's thinking.

The news was first reported by West Virginia political expert Hoppy Kercheval.

Capito would become the first major challenger to announce a Senate campaign and should put the seat of Sen. John D. Rockefeller IV (D-W.Va.) into play immediately. A recent poll showed Capito at 48 percent and Rockefeller at 44 percent in the prospective match-up.

Elizabeth Warren, left, talks with Rep. Shelley Moore Capito (R-W.Va.) and House Financial Services Committee Chairman Spencer Bachus (R-Ala.). (Harry Hamburg/Associated Press)

Capito, the daughter of former West Virginia governor Arch Moore (R), has long been considered the GOP's best hope to follow in her father's footsteps and break the Democrats' longtime hold on statewide office. She has flirted with statewide bids before -- including open Senate and governor's races in 2010 and 2011, respectively -- but had always passed.

It's not clear whether Rockefeller, 75, will seek another term. He is considered one of the more likely retirees in 2014, and Capito's decision should increase the pressure on him to decide sooner rather than later.

The Moore family and Rockefeller have a long and tortured history, with Arch Moore beating Rockefeller in the 1972 governor's race, Rockefeller playing a big role in beating back Moore's failed 1978 Senate campaign, and Rockefeller defeating Moore for governor in 1980. (Moore later returned to the governor's mansion after Rockefeller moved on to the Senate.)

It's unlikely that Capito will face significant opposition in the primary, but among those who have been mentioned are freshman Rep. David B. McKinley and businessman John Raese, whose lopsided loss to Sen. Joe Manchin (D) this year was his fourth loss in a Senate or gubernatorial election.

Republicans have a bevy of opportunities in red states like West Virginia in 2014. About the only other major candidate to step forward is former South Dakota governor Mike Rounds, who has opened an exploratory committee to run for the seat held by another potential retiree, Sen. Tim Johnson (D).