Former President Barack Obama is reportedly growing “increasingly anxious” over Sen. Bernie Sanders’ (I-VT) rise in the polls and is considering issuing a statement on the socialist candidate, Fox Business Senior Correspondent Charles Gasparino reported on Thursday.

According to Gasparino, Obama, who has remained largely silent over the course of the Democrat primary process, is reportedly concerned over Sanders’ recent rise in the polls and could issue a statement on the matter, Democrat Party sources who spoke to Obama claim.

Gasparino reported:

While the former president has not endorsed a Democrat candidate, he reportedly took a veiled shot at the far-left visions of some of the top Democrat contenders, warning a group of liberal donors in November that Democrats need to be “rooted in reality.”

“Even as we push the envelope and we are bold in our vision we also have to be rooted in reality,” Obama said, according to the New York Times.

“The average American doesn’t think we have to completely tear down the system and remake it,” he continued, signaling concern with the far-left field.

He continued:

I don’t think we should be deluded into thinking that the resistance to certain approaches to things is simply because voters haven’t heard a bold enough proposal and if they hear something as bold as possible then immediately that’s going to activate them.

In a profile of the president in November, Politico’s Ryan Lizza noted that Obama views his role in the Democrat primary as “providing guardrails to keep the process from getting too ugly and to unite the party when the nominee is clear.” However, he noted that one exception remained: Bernie Sanders:

Back when Sanders seemed like more of a threat than he does now, Obama said privately that if Bernie were running away with the nomination, Obama would speak up to stop him. (Asked about that, a spokesperson for Obama pointed out that Obama recently said he would support and campaign for whoever the Democratic nominee is.)

Obama allies appear to feel the same way about Sanders. Jim Messina, who served as Obama’s campaign manager in 2012, said this month that President Trump would probably love to run against the socialist senator from Vermont.

Messina told Politico:

If I were a campaign manager for Donald Trump and I look at the field, I would very much want to run against Bernie Sanders. I think the contrast is the best. He can say, ‘I’m a business guy, the economy’s good and this guy’s a socialist.’

From a general election perspective, socialism is not going to be what Democrats are going to want to defend. If you’re the Democratic nominee for the Montana Senate race, you don’t want to spend the election talking about socialism.

Messina issued a similar warning during a Thursday appearance on MSNBC’s Morning Joe:

“He’s beginning to consolidate the Left in his party,” Messina said of Sanders’ recent rise in the polls.

“He has a relationship with these voters, he’s been campaigning with these voters for now six years, he knows New Hampshire voters really well, and people are beginning to come to him,” he continued.

Messina worries that Sanders’ message will fall flat on voters and “get him killed” in a general election matchup, calling him the “worst candidate.”

“I think it’s very clear to me that these swing voters, that I care about, the Trump-Obama voters in Midwestern states, Bernie Sanders is not the candidate we need to beat Donald Trump in November,” he added.