Former Vice President Joe Biden on Thursday said he wasn't ready to rule out the possibility of running for president in 2020, and he also had some criticism for former presidential candidate Hillary Clinton.

"I may very well do it," Biden said at a SALT hedge fund conference in Las Vegas, according to CNN. "Could I? Yes. Would I? Probably not."

After eight years of working in the White House alongside former President Obama, Biden said his priority was to "put back together" his family after his son Beau Biden died of brain cancer in 2015.

"At this point, no one in my family or I have made the judgment to run," Biden told the audience.

Biden also commented on Hillary Clinton's presidential campaign.

"I never thought she was a great candidate," he said. "I thought I was a great candidate."

Biden did have some positive words for Clinton, emphasizing he believed "Hillary would have been a really good president."

If Biden were to run, he would be almost 78 years old on Election Day, making him, if elected, the oldest president in U.S. history.

But Biden said despite being approached by many about the prospect, he still cannot commit to anything.

In the meantime, Biden said that he needs to fulfill several financial promises he has made to his wife, Jill, like paying off their mortgage. Biden has spent his career in public service, having won his senate seat when he was just 30 years old.

Despite his financial obligations, Biden pledged to donate the $200,000 payment for speaking at the conference to charity, according to CNN.

Biden also talked about working with Mr. Obama for nearly a decade, saying they often disagreed on tactics and even had their share of "shouting matches."

Without directly mentioning Mr. Trump, Biden touted Obama's record, noting that the 44th president managed to stay away from any major scandal. Accepting the position of vice president, though, was still not an easy choice, Biden admitted. He said he even originally declined Mr. Obama's offer. Looking back on the experience, Biden called it "the best decision I ever made."

Since Mr. Trump's ascension to the White House, Biden has ruminated about the presidency and what could have been.

"I think I could have won," Biden said in March speech at Colgate University. "I was fairly confident that if I were the Democratic party's nominee, I had a better chance, even, of being president."