Mitt Romney has said time and time again that he has no interest in running for president a third time.

But, on Sunday morning, CBS' Bob Schieffer said not to write off the idea of a 2016 campaign by Romney so quickly.

"I have a source that told me that if Jeb Bush decides not to run, that Mitt Romney may actually try it again," Schieffer said.

During a political panel discussion, the "Face the Nation" host said that he has been told that Romney will consider seeking the Republican nomination for the presidency in 2016 if former Florida governor Jeb Bush chooses to sit the race out.

Romney and Bush are considered similar candidates -- both moderate former governors who enjoy the support of much of the GOP establishment but draw skepticism from the party's conservative ranks.

Several major Romney donors told The Washington Post earlier this year that Bush would be their preferred Republican candidate in 2016.

After shrinking out of the public light following his crushing loss to President Obama in 2012, Romney has slowly reemerged as a coveted political ally for Republicans seeking office this year.

Romney, 67, has begun to embrace the role of party elder, believing he can shape the national debate and help guide his fractured party to a governing majority.

Insisting he won’t seek the presidency again, Romney has endorsed at least 16 candidates this cycle, many of them establishment favorites who backed his campaigns.

The full video of the "Face the Nation" panel discussion is below, with the Romney discussion beginning just after the 9:15 mark.