Just when the Democratic presidential field was beginning to shrink, along comes Michael Bloomberg to expand it.

Maybe. Months after saying he wouldn’t.

A Bloomberg adviser says the billionaire former New York City mayor will file to get on the Alabama primary ballot before that state’s Friday deadline.

Bloomberg phoned “a number of prominent Democrats on Thursday to tell them he was seriously considering the race,” reports the New York Times.

They included former Nevada Sen. Harry Reid, the retired majority leader who remains a significant power-broker in the party.

“Mr. Reid said in a brief interview that Mr. Bloomberg had not explicitly said he was running for president but that the implication of the call had been clear,” the Times says.

Bloomberg “believes that Donald Trump represents an unprecedented threat to our nation” and that “the current field of candidates is not well positioned” to defeat him,” reports the Washington Post, citing a Bloomberg spokesperson.

“With his immense personal wealth, centrist views and close ties to the political establishment, he would present a grave and instantaneous threat to former Vice President Joseph R. Biden Jr., who has been struggling to raise money and assemble a ideologically moderate coalition,” the Times says.

But a campaign would not be easy for the 77-year-old Bloomberg, due to both his political record and Democratic rivals like Sens. Elizabeth Warren and Bernie Sanders, who’ve made clear their opposition to letting the exceedingly wealthy run the country.

“He’s a literal billionaire entering the race to keep the progressives from winning,” Rebecca Katz, a New York-based liberal Democratic strategist, told the Associated Press.

“In March, Bloomberg said that he would not run for president after concluding that his path to the Democratic nomination was narrow and that he could accomplish more as a private citizen,” the Post says.

“I am clear-eyed about the difficulty of winning the Democratic nomination in such a crowded field,” he said then.

Bloomberg has ranged widely in his political affiliation. He’s a former Republican who became an independent, then registered as a Democrat last year. “He actively supported Hillary Clinton in 2016 and blasted Trump … as a con man who overinflates his business success,” the AP says.