The Trump campaign, blindsided by rival Ted Cruz's sudden exit from the race, is now beginning internal deliberations about potential vice presidential candidates, two Trump campaign sources tell CNN.
The campaign will also begin coordinating immediately with the Republican National Committee to calibrate a general election ground game, including staff hires and deciding in which battleground states to deploy field staff, a senior Trump adviser said.
Trump campaign manager Corey Lewandowski told reporters Tuesday night before election results in Indiana drove Cruz out of the race that the campaign had yet to start vetting vice presidential candidates.
Trump confirmed Wednesday that his campaign is beginning to put together a committee to weigh in on his pick for running mate. The committee will include former presidential rival and now-Trump supporter Ben Carson, the former neurosurgeon's adviser Armstrong Williams confirmed to CNN.
Some candidates who have been mentioned by pundits as potential vice presidents are already ruling themselves out.
"Well, I predict Donald's going to have a big win, I like my job. I worked hard to get this job. I'm going to stay in this job," Florida Gov. Rick Scott, one such potential candidate, told CNN's "Erin Burnett OutFront" on Wednesday. "I'm going to finish this job, I've got two years and eight months to go."
When Burnett asked if he would say "yes" to being Trump's vice president, he responded, "I'm going to pass."
"I will do everything I can to make sure he wins both our state and if he wants any help nationwide, I'll do anything I can to make sure he wins but I'm going to stay in this job and finish this job and have a good partner in the White House," Scott said.
On Thursday, Carson told The Wall Street Journal
that he wasn't interested in the job, saying he'd be a "distraction."
A senior Trump campaign source said Wednesday that the campaign's early favorites for vice president are now New Mexico Gov. Susana Martinez, South Carolina Gov. Nikki Haley and Sen. Rob Portman of Ohio.
And Trump, in an interview with CNN on Wednesday, added another name to the list: Ohio Gov. John Kasich, who is expected to drop out of the race Wednesday afternoon.
"I think John will be very helpful with Ohio," Trump told CNN's Wolf Blitzer.
The source stressed that the shortlist is in its infancy.
Some are already taking themselves out of the running: A spokesman for Portman said the senator, who is in the midst of an intense Senate reelection campaign, is "not interested."
"He's focused on his own race," said Kevin Smith, his spokesman.
And Haley said her "plate is full."
"I have great respect for the will of the people, and as I have always said, I will support the Republican nominee for president," she said in a statement. "While I am flattered to be mentioned and proud of what that says about the great things going on in South Carolina, my plate is full and I am not interested in serving as vice president."
Trump said at an event Thursday that Haley was never under consideration.
A spokesman for Martinez also said she wasn't interested.
"The governor has said repeatedly over the years that she isn't interested in serving as vice president," said Chris Sanchez, a spokesman for the governor. "She appreciates that such attention puts New Mexico in the spotlight, but she is fully committed to serving the people of our state."
Haley, who endorsed Sen. Marco Rubio against Trump in her state's primary, has been highly critical of Trump and warned voters against flocking to "the siren call of the angriest voices" -- a thinly veiled dig at Trump.
Martinez has also not shied away from criticizing the brash New York billionaire, but Portman has said he would support the GOP nominee.
One governor who said she was "behind Donald Trump 100%" was Oklahoma Gov. Mary Fallin.
"I have not had any direct contact with Mr. Trump, but I would be very honored if I were to receive a call saying I need you to help make America great again," Fallin said in a statement regarding the VP speculation.
Trump has repeatedly stressed that he would pick a running mate with political and government experience -- versus a businessman like himself -- whose relationships with powerful members of Congress could help him pass his agenda legislatively.