That's news that likely won't sit well with his most glamourous supporter — Scarlett Johansson.
DNAinfo.com New York asked the "Avengers" star last month about swirling rumors that Stringer, who has performed poorly in early mayoral polls, was considering dripping down to the less competitive comptroller's race.
“Not on my watch,” the starlet said. “Appalling. No way. I don’t believe it.
"I won’t hear it,” she added.
Representatives from both Stringer's campaign and his office have refused to comment on the reports about dropping out of the race.
Unlike most celebrity supporters who quietly write checks or splash their names on fundraiser invitations to draw guests, Johansson — whose twin brother Hunter was once a staffer in the borough president’s office and whose grandmother worked with Stringer in the 1980s to preserve affordable housing — has become a pivotal part of Stringer's campaign.
She has headlined multiple fundraisers, including a $2,500-a-head cocktail party held at a private residence at the Plaza Hotel, a glitzy bash at Chelsea’s Maritime Hotel, and appeared at his side at other events, including a recent premier for the film "Gasland."
She also contributed $4,950.00 of her own cash to the campaign in October 2011 — the maximum contribution for either a mayoral or comptroller run. (Her brother has been less generous, however, giving Stringer $20 in May 2011 and $175 in June 2011.)
"When Scott is elected mayor, New Yorkers can expect a representative who is focused on making New York a cleaner, greener city, preserving its affordability and the integrity of our varied communities," she gushed in the invitation to the Chelsea fundraiser, where she sung his praises to the crowd.
Other mayoral hopefuls have also been racking up nods from the celeb set.
As Stringer was partying in Chelsea, for instance, City Council Speaker Christine Quinn was wooing her LGBT supporters at the old Boom Boom Room atop the Standard Hotel, along with Project Runway's Tim Gunn, Bravo television exec Andy Cohen and designer Isaac Mizrahi, the Wall Street Journal reported at the time.
Quinn has also made frequent fundraising trips out of state, including a jaunt to Los Angeles last June, when she received contributions from Tom Hanks, producer Rob Reiner and Universal Studios President Ronald Meyer.
She's also wooed rock star Jon Bon Jovi, Vogue editor Anna Wintour and celebrity chef Mario Batali. Public Advocate Bill de Blasio, meanwhile, has crooner Paul Simon and actor Steve Buscemi on his team, noted Capital New York.
Lady Gaga also gave Stringer a major media boost — and a spike in his Twitter following — when she tweeted a thank you to him for defending her after Staten Island Borough President James Molinaro called her "a slut."
But what impact celebrity backers can have on local candidates is "negligible," observers said.
Stringer appeared to receive a slight bump in the polls after Johansson endorsed him back in September, 2011.
His position in a theoretical Democratic primary rose from just 4 percent in July 2011, up to 7 percent by the end of October that year — though he remained dead-last among the major candidates, according to Quinnipiac polls.
But since then, his numbers have slumped again.
The most recent Quinnipiac poll this May put him back at just 4 percent, far behind City Council Speaker Christine Quinn (26 percent), former Comptroller Bill Thompson (13 percent) and Public Advocate Bill de Blasio (10 percent.) Even scandal-scarred Comptroller John Liu, whose fundraising is under federal investigation, earned nearly twice as much support as Stringer with 7 percent.
“Neither Scarlett Johansson or any other celebrity really brings votes to the table," said Baruch College Professor Doug Muzzio, who equated the efforts to "chicken soup" — something that can't hurt, but might not help much.
Nonetheless, he said a high-enough profile backer could enhance a candidate's fundraising by hosting events, and attracting headlines.
"What it does bring is it brings media attention," he said.
As for Scott and ScarJo?
“My speculation is no," he said. "It hasn’t mattered much at all."