The Democratic National Committee (DNC) has proposed moving forward with the virtual roll call for delegates to select a presidential nominee ahead of their in-person convention in Chicago on August 19, party leadership said Monday evening during a press briefing.

The party has not proposed a date when the virtual roll call will begin, but DNC Chair Jaime Harrison said they will still deliver a nominee by Aug. 7, but may come as soon as Aug. 1.

A DNC official also confirmed during the briefing that only pledged delegates -- and not automatic delegates (superdelegates) -- can vote on the first round of virtual roll call voting (first ballot), unless any candidate has secured a majority of all delegate votes. It is also possible for automatic delegates to vote on the first ballot -- though it would not be easy, according to the DNC official, and could only happen if a candidate were to submit a majority of the convention delegates in support of their nomination petition, rather than a required 300 delegate signatures.

On Monday, Harrison and Democratic National Convention Committee Chair Minyon Moore said that the truncated virtual process, which was proposed after a ballot access issue in Ohio that has since been resolved, will still "ensure" that their nominees are on the ballot in all 50 states and the District of Columbia.

"There is still a need for a virtual component to our nominating process. That has not changed, as we laid out in May, we are committed to meeting valid access deadlines," Moore said.

“Immediately after President Biden withdrew from the race, Republican leaders, including Speaker Mike Johnson, made clear that they would file losses to challenge the Democratic nominee's place on the ballot. That's why we are working in close collaboration with the convention Rules Committee on a framework for the nominating process, which will incorporate an electronic voting system to ensure we meet these deadlines,” she added.

Delegates will be informed about possible candidates through a "a candidate directory" that will be provided to them, and delegates can opt into communications from those candidates.

A DNC official later clarified that interested candidates can be included in the directory even before reaching 300 signatures.

-ABC News' Oren Oppenheim and Isabella Murray

President Joe Biden is scheduled to return to the White House Tuesday for the first time since announcing he is stepping aside from the 2024 presidential race.

The return also comes after the president began isolating in Rehoboth, Delaware, after testing positive for COVID-19 last week.

Biden will depart Delaware Tuesday afternoon and is estimated to be back at the White House by 2:30 PM ET.

No other events are currently on the president's schedule.

Sen. Bernie Sanders, I-Vt., said Monday night that he wants to see Vice President Kamala Harris campaign for president "on issues of importance for the working class of this country."

In an interview with Linsey Davis on ABC News Live, Sanders said he wants Harris to "stand up to corporate greed and massive income and wealth inequality."

He also called for her to support raising the minimum wage and expand Social Security and Medicare. Sanders also said he wants Harris to "demand that the wealthy start paying their fair share of taxes."

If Harris takes on those issues, Sanders said he believes she "can win big," but he still wants to “have just another conversation” with the vice president.

Sanders had been supporting President Joe Biden in the 2024 election before Biden's withdrawal from the campaign on Sunday night.

"This has been a very unprecedented situation. I am not overjoyed about the way that President Biden was treated," Sanders said. "We are where we are right now, and I'm 99% sure that the vice president will be the nominee. And then she has an excellent chance to win this election."

While he still has plans to speak with Harris, he is committed to keeping former President Donald Trump from returning to the White House.

"Well, I'm going to do everything I can to see that Donald Trump, [the] most dangerous president in American history, is defeated," Sanders said.

-ABC News' Maria Olloqui and Jolie Lash

The American Federation of Labor and Congress of Industrial Organizations has thrown its unanimous support behind Kamala Harris in the 2024 presidential race.

"From day one, Vice President Kamala Harris has been a true partner in leading the most pro-labor administration in history," AFL-CIO President Liz Shuler wrote in a statement Monday.

"At every step in her distinguished career in public office, she’s proven herself a principled and tenacious fighter for working people and a visionary leader we can count on," Shuler continued.

"From taking on Wall Street and corporate greed to leading efforts to expand affordable child care and support vulnerable workers, she’s shown time and again that she's on our side. With Kamala Harris in the White House, together we'll continue to build on the powerful legacy of the Biden-Harris administration to create good union jobs, grow the labor movement and make our economy work for all of us," she added.

The support for Harris' campaign comes as some of the nation's largest unions also have offered support, praise and outright endorsements to the vice president.

The Service Employees International Union, whose 2 million members make it the nation's largest private sector union, endorsed Harris on Sunday. So did Local 3000 of the United Food and Commercial Workers, a labor organization in the Pacific Northwest, which drew attention last week when it became the only Biden-aligned union to call for him to step aside.

-ABC News' Beatrice Peterson and Max Zahn