When Bernie Sanders’ aides sent out a memo this week revealing that the Vermont senator hadn’t closed the door to a third bid for president, they blasted it far and wide.

That was precisely the point: While Sanders has no current plans to run in 2024, no one should forget that he remains popular, is the undisputed leader of the progressive left and that he must be part of any conversation about a potential open Democratic presidential primary. Until now, he wasn’t.

A person close to the process said Sanders approved the concept and execution of the memo.

“I know people who got it who weren’t Bernie staff, who were other Democrats friendly with Bernieworld but not known as hardcore Bernie-ites,” said a former Sanders campaign aide, who requested anonymity to speak frankly about the memo. “They wanted it out.”

Added another former staffer: “They sent this to people who have relationships across the press because they wanted to make news.”

President Joe Biden has said he plans to campaign for another term, but some Democrats doubt he’ll pull the trigger. He would be 82 years old at the start of a second term, and his current job approval ratings are dismal. In political circles, speculation has been rampant that potential Democratic candidates in an open primary could include Vice President Kamala Harris, Transportation Secretary Pete Buttigieg, Sen. Elizabeth Warren, and even some Sanders allies.

But not Sanders himself.

He has been largely absent from presidential chatter, despite finishing as the runner-up in the past two presidential primaries.

A ranking last week of the top 10 Democratic candidates in 2024 did not include Sanders in the list. The New York Times reported last week on a forthcoming book by Ari Rabin-Havt, Sanders’ 2020 deputy campaign manager, in which he wrote, “While Bernie Sanders will never be president, his two campaigns have transformed the Democratic Party and this country.”

Jeff Weaver, Sanders’ longtime adviser and 2016 presidential campaign manager, along with former top Sanders adviser Mark Longabaugh, has privately encouraged California Rep. Ro Khanna to run in 2024 if Biden doesn’t try for a second term. Khanna previously served as Sanders’ campaign co-chair.

Another past campaign co-chair to Sanders, Nina Turner, recently predicted that a progressive would challenge Biden in 2024 and notably declined to comment when asked if she would consider being the person to do it.

“There’s a lot of uncertainty in the political environment at the moment,” said Weaver. “It’s very early in the process, but the point of the memo, which I did not have a hand in drafting, is just to alert folks that if the president does not run in 2024, that the senator has not closed the door on it.”

Sanders has made moves recently that likely would have been seen as the maneuverings of a prospective presidential candidate if done by other politicians. Last summer, he traveled to Iowa and Indiana to promote Biden’s spending plan. In December, he visited Michigan to rally Kellogg’s workers on the picket line. He is making trips to Virginia and New York City this weekend to visit unionizing workers at Amazon and Starbucks.

But Sanders’ advanced age, along with the fact that his aides and allies had signaled that he would not run again, seemed to foreclose the possibility of a third run. The Vermont senator, who was born 14 months before Biden, is 80 years old, and had a heart attack while on the campaign trail in 2019.

Against the current political backdrop, however, Sanders’ age hardly stands out. Aside from Biden, former President Donald Trump, who could make another bid for the White House in 2024, is 75 years old. House Speaker Nancy Pelosi is 82, and Senate Minority Leader Mitch McConnell is 80.

Still, some allies hope Sanders doesn’t run a third time and passes the torch instead.

Kurt Ehrenberg, Sanders’ former senior adviser in the early-voting state of New Hampshire, called the memo this week “good for business” because it “keeps Bernie in the game, it keeps his name in the mix.”

But, he said, “It’s not a good idea for Bernie Sanders to be thinking about running for president of the United States. … It’s time for the progressive movement to find new leadership. He’s just too old, and we need young people leading a movement that’s going to save this country.”

One former top aide dismissed the memo as a “plea to stay relevant and a part of the 2024 conversation should Biden decide not to run again.”

Some people close to Sanders have encouraged him to keep 2024 as an option, depending on Biden’s political fortunes. In private conversations with others, Sanders confidants have said he is open to running again, according to two people familiar with the discussions.

Some Sanders allies are even declaring that they’d be with him if he campaigned in an open primary in two years.

“Bernie Sanders is the most consequential progressive leader of a generation who also happens to be the most popular current elected official,” said Khanna. “He has won the debate to end neoliberalism, support working families and rebuild the middle class in places that were deindustrialized. I will be enthusiastically for him for whatever he runs for.”