(CNN) Vice President Joe Biden urged patience Wednesday when asked whether Vermont Sen. Bernie Sanders should get out of the presidential race now that Hillary Clinton has become the presumptive Democratic nominee.

"I think that's his call," Biden said while leaving the Senate chamber. "It's clear we know who the nominee is going to be. I think we should be a little graceful and give him the opportunity to decide on his own."

After deciding not to enter the race himself, Biden often made favorable comments about Sanders but did not endorse a candidate.

Later the White House said Sanders has "more than earned the right to make his own decisions about his campaign," White House press secretary Josh Earnest said, President Barack Obama won't be publicly calling for him to step out of the race. Obama and Sanders are expected to meet Thursday at 11:15 a.m. ET.

After he meets with Obama tomorrow, Sanders is scheduled to meet with Senate Minority Leader Harry Reid at the Capitol. Reid has maintained close contact with Sanders throughout the campaign, but has occasionally chafed at him, including ripping Sanders' response to the chaos at the Nevada Democratic convention last month.

Sanders supporters on the Hill -- a small group of liberal lawmakers -- split on what the senator should do now that Clinton had secured the nomination.

Rep. Tulsi Gabbard called on him to stay and fight through the convention -- a prospect that even other Sanders supporters were not embracing.

But Sen. Jeff Merkley, the lone senator to endorse Sanders, said he expected Sanders to stay in the race through next Tuesday, when voters in Washington cast the final ballots of the 2016 primary contest.

"He has pledged to make sure that he stayed in the race through the last primary, which is next Tuesday, and he'll honor that promise," Merkley, an Oregon Democrat, told CNN.

Merkley called Clinton "our nominee" and said he expected Sanders' meetings in Washington Thursday to focus on how to "bring the halves of the party together."

"We have our nominee, and the conversation is about how to bring the party together," he said.

House Democratic leaders were not ready to give him a hard push out the door, instead hewing closely to a script set by the Clinton campaign that leaves the decision to Sanders.

"I believe that only Sen. Sanders can make that judgment," said Rep. Steve Israel, a New York Democrat and former head of the House Democrats' campaign arm. "In 2008, when Hillary Clinton understood that President Obama had enough delegates to secure the nomination, she did some deep thinking and emerged from that process, understanding that it was critical that we united around our presumptive nominee. We did that and he was president for two terms. Sen. Sanders I'm sure will be entertaining those thoughts."

The tightrope walk comes as Sanders is set to meet with Obama and Senate Minority Leader Harry Reid to discuss his future plans.

But at least one Democratic lawmaker said it was time for Sanders to hang it up -- just hours after Hillary Clinton became the first woman to become the presumptive nominee of a major party.

Asked if it was time for Sanders to leave the race, Rep. Ruben Gallego, an Arizona Democrat, said it was time for him to leave.

"Essentially, yes, of course," Gallego told CNN's Alex Rosen. "It's time for Bernie to recognize that this race is a race about unity as a ticket and figure out a way to exit."

But House Democratic leaders, gathered for a weekly meeting just hours after Clinton's decisive wins in California, New Jersey and elsewhere Tuesday, were hesitant to go so far.

Instead, they said they hoped Sanders would see the light on his own -- namely the prospect of Donald Trump in the White House if they don't all get behind Clinton.

"Bernie Sanders understands, probably better than anyone else right now, just what a threat a Trump presidency would be, the fraud of Trump -- Conman Don -- becoming president of the United States and what that would mean, not only to the United States, but to the world," Rep. Joe Crowley, vice chair of the House Democratic Caucus said.

Biden has previously praised Sanders for thinking big when it comes to how to lead the country.

"I like the idea of saying, 'We can do much more,' because we can," Biden told The New York Times in April.

"I don't think any Democrat's ever won saying, 'We can't think that big -- we ought to really downsize here because it's not realistic,'" Biden added.

He lauded Sanders for being at the forefront of addressing issues like the growing gap between the rich and poor.

"Bernie is speaking to a yearning that is deep and real. And he has credibility on it," Biden told CNN's Gloria Borger in January.

"It's relatively new for Hillary to talk about that," Biden continued, acknowledging that Clinton has "come forward with some really thoughtful approaches to deal with the issue" of income inequality.

Biden expressed little shock that Sanders was drawing ample support, which some thought would be difficult for a candidate who identified as a democratic socialist.

"If Bernie Sanders never said he was a democratic socialist, based on what he's saying people wouldn't be calling him a democratic socialist," he said earlier, claiming Clinton entered the race with an "awful high bar for her to meet."