Tempermentally, the two Republicans match up well. But Pawlenty is just a born again Romney to a lot of GOP activists.

Politico:

Tim Pawlenty has jumped to the top of the vice presidential shortlist of several Mitt Romney advisers after emerging as the most effective -- and well-liked -- surrogate for the GOP nominee-to-be, according to several Republicans familiar with campaign deliberations.

The former Minnesota governor has impressed top Romney officials with his winning onstage presence at a grueling roster of Republican events throughout the country and with his low-maintenance personal style that has made him a favorite with the campaign's tight-knit inner circle at the Boston headquarters.

Pawlenty is strong where Romney is weak - with the regular-guy, working-man connection with voters in casual settings.

"Pawlenty will walk up and put a supporter in a headlock," said a Republican consultant who was startled to witness just that. "He provides a nice yin and yang to Romney."

Several top Republicans said that as the hockey-playing son of a blue-collar worker, and a longtime champion of connecting with what he has called "Sam's Club Republicans," Pawlenty would be comfortable campaigning among working-class voters in a way that Romney never will be.

In addition, Pawlenty is an evangelical Christian but is low-key enough about his faith that he doesn't scare off secular voters. This could help Romney with religious conservatives who may be skeptical of - or even hostile to - his Mormon faith.

This election is going to be so close that Romney is going to be tempted to choose a candidate who can actually bring him an important state, or help him with a vital constituency. I still wouldn't rule out Rubio despite his stock falling in recent weeks. And reports that Senator Rob Portman of Ohio is the man to beat make sense in that it is possible Portman could swing Ohio to Romney.

Pawlenty and Rep. Ryan would be long shots at this point - Pawlenty with better odds given how highly the Romney people evidently think of him. But A Romney-Pawlenty ticket wouldn't excite too many peope. And if enthusiasm is going to be vital for Romney to win, he probably can't afford to choose the former Minnesota governor.