With Mitt Romney abroad, his vice presidential contenders go on the attack

With Mitt Romney overseas, his team has dispatched an army of vice presidential contenders to swing states around the country to campaign in the presumptive GOP nominee's place.

The Number Two spot on the ticket usually plays the attack dog role and these campaign stops will be seen as try out roles for running-mate wannabes.

Louisiana Gov. Bobby Jindal, Virginia Gov. Bob McDonnell, Sens. Marco RubioMarco RubioSenators introduce new Iran sanctions Senate intel panel has not seen Nunes surveillance documents: lawmakers With no emerging leaders, no clear message, Democrats flounder MORE (R-Fla.), John ThuneJohn ThuneLawmakers want infrastructure funded by offshore tax reform Senate GOP hedges on ObamaCare repeal timeline Week ahead: Robocall crackdown tops FCC meeting agenda MORE (R-S.D.) and Rob PortmanRob PortmanOvernight Finance: Senators spar over Wall Street at SEC pick's hearing | New CBO score for ObamaCare bill | Agency signs off on Trump DC hotel lease GOP senators offer bill to require spending cuts with debt-limit hikes Vulnerable Senate Dem: Border tax concerning for agriculture MORE (R-Ohio), former Minnesota Gov. Tim Pawlenty, and Rep. Paul RyanPaul RyanFox News host promoted by Trump calls on Paul Ryan to step down Dan Rather: Failure to repeal ObamaCare most 'staggering loss' so early in a term Sunday shows preview: Aftermath of failed healthcare bill MORE (R-Wis.) are among those making appearances for Romney.

Several of these men are said to be top contenders for the running mate job. Other names that have gotten buzz, but are missing, are Sen. Kelly AyotteKelly AyotteFEC commissioner to Trump: Prove voter fraud Live coverage: Day three of Supreme Court nominee hearing Lewandowski saw no evidence of voter fraud in New Hampshire MORE (R-N.H.) and New Jersey Gov. Chris Christie. Ayotte, however, will be joining Sen.s John McCainJohn McCainMcCain: Trump admin must fill State Dept. jobs McCain says he hasn't met with Trump since inauguration Overnight Defense: General warns State Department cuts would hurt military | Bergdahl lawyers appeal Trump motion | Senators demand action after nude photo scandal MORE (R-Ariz.) and Lindsey GrahamLindsey GrahamGraham: 'I'm glad' Ivanka will be working in the White House Trump tweets promotion for Fox News show GOP senators pitch alternatives after House pulls ObamaCare repeal bill MORE (R-S.C.) on of swing states that could face defense cuts under sequester.

Jindal, who's campaigning in Iowa before moving on to Florida on Saturday, has emerged as one of Romney’s fiercest and most visible surrogates. The governor has also been one of President Obama’s harshest critics — a role he has played since his withering attacks against the federal government following the BP oil spill in the Gulf of Mexico.

He was joined in Iowa by McDonnell, whose running mate prospects had been said to have fallen, especially after he was tapped to lead the platform committee at the Republican National Convention. His reemergence on the campaign trail will likely lead to speculation he's risen in the eyes of Team Romney. Jindal is seen as a top contender for the spot.

Romney has said he won't name a running mate while he's overseas. The only time line his campaign has given is to say the choice will be announced before the Republican National Convention begins in Tampa, Fla., on August 27.

Rubio also has seen his stock rise and fall as a possible vice presidential candidate. Recently he’s been on the upswing, as some in the party have said Romney’s struggles during his foreign trip might mean he should shirk a safe vice presidential pick for a candidate with more upside.

The freshman senator will be campaigning for Romney in the swing-state of Nevada and in Iowa this weekend. Rubio is the only candidate Romney has confirmed is being vetted. The others are known only to the presumptive nominee and Beth Myers, his aide leading the vetting team.

Myers added fuel to the VP fire on Friday when she tweeted out a list of suggestions for people to follow on Twitter that mirrors the likely vice presidential shortlist.

The names included: Ayotte, Pawlenty, Christie, Jindal, Rubio, Ryan, Former House Speaker Newt Gingrich, Portman, McDonnell, former Secretary of State Condoleezza Rice, Thune, New Mexico Gov. Susanna Martinez, and former Sen. Rick Santorum (R-Penn.).

Some of the names — like Gingrich and Santorum — are highly unlikely to be on the list, given the contentious Republican primary and their limited contact with Romney since he became the presumptive GOP nominee. Martinez was an early contender whose name sparked a great deal of buzz but she has told New Mexico papers she's not interested in the job. Rice's name skyrocketed up the list when the influential website the Drudge Report listed her as a favorite.

Neither woman is set to campaign for Romney this weekend.

Meanwhile, Ryan, the House Budget Committee chairman, will join Republican National Committee Chairman Reince Priebus on a bus tour through Wisconsin on Sunday, according to ABC News.

And Portman, said to be a top VP contender, has campaign stops scheduled in Ohio and Pennsylvania this weekend and on Monday.

Pawlenty, who's another leading contender, will campaign for Romney in North Carolina over the weekend.

And Thune, who's seen as dark horse VP candidate, was part of the GOP’s “you didn’t build this” offensive in Virginia on Thursday and will open a Romney campaign office in the state over the weekend.

Romney returns from his trip on Wednesday.

— Alicia M. Cohn contributed