Former New York City Mayor Michael Bloomberg appears to be seriously considering entering the 2020 race for president.

Bloomberg is expected to file paperwork this week designating himself as a candidate in Alabama's Democratic presidential primary, Fox News has learned.

Bloomberg had announced earlier this year that he would not seek the party's nomination. But, in a statement obtained by Fox News Thursday, his political adviser Howard Wolfson said Bloomberg was worried that the current crop of Democrats seeking the White House was "not well-positioned" to defeat President Trump.

"In 2018 [Bloomberg] spent more than $100 million to help elect Democrats to ensure that Congress began to hold the President accountable," Wolfson said. "And this year he helped Democrats win control of both houses of the Virginia legislature."

He added: "We now need to finish the job and ensure that Trump is defeated -- but Mike is increasingly concerned that the current field of candidates is not well positioned to do that."

Bloomberg's expected move has come amid increasing concern about the leftward drift of the major Democratic candidates, the departure of candidates who failed to gain traction – and talk of other potential late entries.

A Washington Post columnist tweeted Thursday that former Obama Attorney General Eric Holder has been consulting strategists about possibly jumping into the Democratic presidential race.

Bloomberg, a billionaire businessman, reportedly has been mulling over a potential White House run for weeks but has not made his final decision. His move to send staffers to Alabama to gather the signatures needed to qualify for the primary is the first sign that he is seriously considering entering the Democratic fray.

MICHAEL GOODWIN: MICHAEL BLOOMBERG, IT'S TIME FOR YOU TO ENTER THE 2020 PRESIDENTIAL RACE

"Welcome to the race, @MikeBloomberg!" tweeted Massachusetts Sen. Elizabeth Warren, who has been among the candidates criticized by centrists for liberal policies, including support for "Medicare-for-all."

Alabama is not an early voting state, but it has a deadline of Friday for candidates to officially enter the presidential race.

CLICK HERE TO GET THE FOX NEWS APP

If Bloomberg does enter the presidential race, he would be the second billionaire vying for the Democratic nomination. Earlier this year, hedge fund manager Tom Steyer entered the race after months of pushing an effort to impeach Trump.

A recent Fox News poll found that Bloomberg’s chances for winning the White House are not promising, with 32 percent of respondents saying they would never vote for him, compared to just eight percent who would definitely cast a ballot for the billionaire businessman.

Fox Business Network's Trish Regan and The Associated Press contributed to this report.