It seems like probable Republican nominee Mitt Romney has already forgotten that former rival Rick Santorum recently called him a liar and the "worst Republican in the country."

During a town hall-style event in Warwick, Rhode Island on Wednesday, Romney insisted that he had not ruled out the former Pennsylvania senator as a vice presidential nominee.

"Everybody is on my list," the candidate told a man who asked if Santorum would be considered as a vice presidential candidate. "I'm not taking anybody off the list."

Romney clarified: "I actually don't have a list yet. So, I can't say that someone is on or off my list, but I can tell you that the people that I had the privilege of running against would surely be among those I'd consider. The criteria has to be first and foremost is this a person who could be president of the United States if that were needed? And do people recognize that and see that as the kind of person who has that qualification."

"And so he -- I've said this before: If any of the people I ran against happened to become the nominee, I would have endorsed them and supported them for president. So, of course they'd be on that list, and he among others."

Over the course of a bitter primary, Santorum had suggested that Romney was "lying" about his health care record, called him the "ultimate flip-flopper," said that the country "might as well stay with" President Barack Obama, insisted that the Massachusetts Republican was a "weak candidate" and charged that he was the "worst Republican in the country."

On Wednesday, Romney predicted that Santorum would eventually join him on the campaign trail.

"You’ll see us all come together in a powerful way, but the time for that will happen down the road as we spend more time together and hit the trail together," Romney told Fox News. "You will see our part more united than it’s been in a long, long time in part because President Obama has taken America in such a different course than we have ever gone as a nation before."