WASHINGTON (Reuters) - Former Massachusetts Governor Deval Patrick has told supporters he will join the Democratic race and run for president, media outlets including the New York Times reported on Wednesday.

Patrick, who was the state’s first African-American governor and is close to former President Barack Obama, is widely respected within the Democratic party but faces a steep uphill climb if he joins the race.

He would join a field of nearly 20 candidates vying for the party’s nod to run against Republican Donald Trump in 2020, most of whom have failed to win more than a few percentage points of support in national and state polls. He has already missed deadlines to get on the ballot in Alabama and Arkansas, as well as for the party’s upcoming debate in Atlanta.

The field is currently dominated by former Vice President Joe Biden, a moderate, and two liberals: U.S. Senator Elizabeth Warren of Massachusetts and U.S. Senator Bernie Sanders of Vermont.

On Tuesday, former New York Mayor Michael Bloomberg also took steps to underpin a possible run, filing paperwork to appear on the primary ballot in Arkansas. The same day, former Democratic standard-bearer Hillary Clinton gained attention when she refused to rule out a possible run in a BBC interview.

Patrick, 63, is a Harvard-trained lawyer and two-term former governor who has been working as a managing director of Boston investment firm Bain Capital since 2015, running a socially responsible investing fund.

He considered but rejected joining the race last year, but on Wednesday was phoning Democratic supporters to let them know he intended to run, the New York Times reported, citing two party officials.

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Patrick’s run would likely be announced on Thursday, possibly in a video, cable network CNN reported, citing people familiar with the matter.

The heated talk of late entry by party stalwarts shows the volatility of the race and highlights Democrats’ worries that the candidacy of frontrunner Biden may be weakening.

The apparent ascendance of Warren also concerns many Democrats, who fear the liberal firebrand may not draw enough enthusiasm among moderate voters and Republicans who dislike Trump to propel a winning campaign against him.

As governor, Patrick is credited with implementing the state’s healthcare reform plan, passed under his predecessor, Republican Mitt Romney, and reforming its pension system.