Joe Biden has gotten the boss's "blessing."
CNN has reported that President Barack Obama has told the veep he would not stand in his way or counsel him against a run.
A senior Democratic source told the network that if the former Delaware senator does run, he would announce by Oct. 1.
Insiders, however, worry that a late entry by Biden would be seen as a slap at many Democrats enamored by the idea of electing the first women president.
Biden, who recently met with the head of the Democratic party's progressive wing, Sen. Elizabeth Warren of Massachusetts, is said to be worried that Clinton simply cannot speak to the income inequality issue.
CNN said Biden is leaning toward running as Clinton continues to be dogged by Republicans about her secret email servers.
Reuters reports, however, that Clinton's big bucks donors are still solidly with her.
"I like Joe Biden very much, but it's time to line up for Hillary and we are lining up," said Karin Birkeland, a top Democratic bundler for President Barack Obama in 2012 who recently committed to Clinton.
"She has by far the best resume, she's ready, she's younger and she's a woman."