Associated Press
Republican presidential candidate, former Massachusetts Gov. Mitt Romney, right, and Sen. Rob Portman, R-Ohio, call eligible voters from his campaign headquarters in Charleston, S.C., Thursday, Jan. 19, 2012.

A growing chorus of voices is suggesting that Sen. Rob Portman, R-Ohio, leads Florida Sen. Marco Rubio and New Jersey Gov. Chris Christie in the unofficial race to become Mitt Romney's vice-presidential selection.

On Wednesday, Real Clear Politics writer Erin McPike penned a piece outlining the prevailing wisdom as to why it would make sense for Romney to pick Portman as a running mate: The two men share enough in common to work well together, and the Ohio senator possesses some critical qualities that Romney sorely lacks.

"Like Romney, (Portman) is universally known as a 'numbers guy,' requiring copious amounts of data from his staff or the staffs of those deploying him before he goes into any meeting or interview. And that’s part of the reason why Romney likes him so much and respects his intelligence …

"(Portman) is a hunter and — unlike Romney — knows what he’s hunted. In some areas of the country, that’s virtually a requirement to be a card-carrying member of the GOP. … One of the qualities that might make him most valuable to Romney — who many political observers think needs a Latino on the ticket to neutralize the president’s edge with that group — is Portman’s fluency in Spanish. … His courtship of the press in many ways makes him the antidote to Romney, who has a penchant for avoiding the media."

McPike's new Real Clear Politics article comes hot on the heels of recent stories in the Beltway-centric National Journal that ran beneath the headlines "Congressional insiders agree: Rob Portman" and "Rob Portman leads Republican Veepstakes."

The futures market Intrade currently assigns the following probabilities regarding who will be Romney's running mate: Rubio, 20 percent; Portman, 18 percent; and Christie, 7.4 percent.

Even though Christie appears to be something of a dark horse at this point in the GOP's VP derby, Real Clear Politics publisher David DesRosiers doesn't think the New Jersey governor is out of the running just yet. DesRosiers, in reviewing the new book “Chris Christie: The Inside Story of His Rise to Power,” wrote Friday, "Most important … this unorthodox New Jersey alpha male might be the best possible complement to Mr. Romney and his would-be administration. … If Mr. Romney is able to 'look out the door' at the talent of his team, rather than being a 'look in the mirror' type of leader, Chris Christie’s big personality is a big asset."