JERSEY CITY -- Political experts have long predicted that the battle for the Democratic nomination for governor next year would be a crowded, bruising race with three top contenders: Jersey City Mayor Steve Fulop, former banking executive Phil Murphy, and state Senate President Stephen Sweeney.
On Wednesday, though, that field suddenly shrunk.
Fulop announced out of nowhere that he won't seek his party's nod -- a shocking move that reshapes the race to succeed Republican Gov. Chris Christie.
In a news conference outside of city hall in the state's second-largest city, Fulop said he will instead support Murphy, the ex-Goldman Sachs executive and U.S. ambassador to Germany who is the only 2017 hopeful to officially declare his candidacy.
Fulop, a 39-year-old rising star in New Jersey politics, had spent three years mulling a bid at the governor's office, appearing at events across the state and being supported by a super PAC that had raised millions.
Instead, Fulop said he will run for a second term as mayor, adding that he doesn't "see any winners ultimately in a very, very bloody primary."
"The reality is: I think this will be a good thing for Jersey City and a good thing for New Jersey," he said, standing next to Murphy at the news conference.
Murphy said the goal is "unifying the Democratic party and getting the state back on track."
Now, experts say the race has been transformed into a north vs. south Jersey battle -- between Murphy, a Middletown resident whose campaign is based in Newark, and Sweeney, a Gloucester County politician who is the leader of the upper house of the state Legislature.
Patrick Murray, director of the Monmouth University Polling Institute, said Murphy -- who has infused his campaign with a $10 million loan -- is now the front-runner.
"This is a game-changer," Murray said. "At the beginning of the year, I gave Murphy very little chance of grabbing the nomination. Within the last few months, he became a bona fide player. Now you have to peg him as the odds-on favorite."
Experts say whoever wins the Democratic nod is the favorite to win the general election to succeed Christie, whose approval ratings is in the 20s.
Matthew Hale, a political science professor at Seton Hall University, said Sweeney is "still the Democrat with the most name ID."
"But if Murphy can take over Fulop's north Jersey and liberal supporters, it could be a real dog fight," Hale said.
Appearing at an unrelated news conference Wednesday, Sweeney said it's "no surprise to see two for Goldman Sachs workers embrace."
Fulop also worked at the banking firm before his political career.
There are also a number of other Democrats who could enter the race: Tom Byrne, the son of former Gov. Brendan Byrne and head of the New Jersey State Investment Council; Essex County Executive Joseph DiVincenzo; state Sen. Raymond Lesniak (D-Union); state Assemblywoman Shavonda Sumter (D-Essex); and Assemblyman John Wisniewski (D-Middlesex).
Lesniak said Wednesday that Fulop "teaming up with Murphy and all his money" hurts his own chances.
"But I never back down from a challenge in my life," said the veteran lawmaker, who added that he will declare his candidacy in "a couple of weeks."
Wisniewski said he will announce his plans after November's presidential election. He added that "what Steve Fulop does or doesn't do doesn't affect my decision-making."
State Democratic Chairman John Currie said he's sorry to see Fulop go.
"I think he would have been a good candidate, but it's his decision," Currie said.
The chairman did acknowledge that Fulop's decision narrows the field of candidates, which may not be a bad thing considering the cost and energy involved with a large primary election.
"I guess you can say it's a relief," Currie said. "Many of us had not made up our minds."
Possible contenders for the Republican nomination include Assembly Minority Leader Jon Bramnick (R-Union), Evesham Mayor Randy Brown, Assemblyman Jack Ciattarelli (D-Somerset), Lt. Gov. Kim Guadagno, and state Senate Minority Leader Tom Kean Jr., the son of former Gov. Tom Kean.
Fulop's announcement comes a day after his name surfaced at the Bridgegate trial, which experts said could have complicated his candidacy.
According to testimony, members of Christie's inner circle wooed the mayor and other Democrats to endorse the governor's re-election bid in 2013. But after it became clear Fulop wouldn't bite, Christie's allies canceled a series of planned meetings with the mayor.
But Fulop dismissed the idea that would hurt him.
"It's very clear from the prosecution's opening statements that I was mistreated," he said.
NJ Advance Media staff writers Adam Clark and Susan K. Livio contributed to this report.
Brent Johnson may be reached at bjohnson@njadvancemedia.com. Follow him on Twitter @johnsb01. Find NJ.com Politics on Facebook.