Ben Carson is leaving the door cracked to a run for president in 2016, but just barely.

"If a year and a half goes by, and people are still clamoring for me to do that, and there's no other very good candidate, I would certainly have to seriously consider it," he said on CNN's "The Lead with Jake Tapper."

But he proceeded to say that "the likelihood of that is incredibly small. So I'm not really planning on that."

Buzz has been building for a potential Carson candidacy ever since his National Prayer Breakfast speech last month excited conservatives. Carson is soon retiring from his medical practice and seemed to toy with the idea that he might run for president at last weekend's Conservative Political Action Conference.