The person spoke on condition of anonymity because Spitzer was only speaking to The New York Times. Spitzer, a Democrat, stepped down from the governor's office in 2008 over a prostitution scandal.
Spitzer has spoken in the past about the potential for the comptroller's job to look into corporate misdeeds. That would be similar to what he did as the state's attorney general.
Candidates for citywide offices like comptroller have to have 3,750 signatures from registered voters in their party by Thursday.
The Times first reported the story on Sunday.
In speaking to the Times, Spitzer said he hoped city voters would give him a chance.
"I'm hopeful there will be forgiveness, I am asking for it," the Democrat said.
Current Comptroller John Liu is running for mayor.
Manhattan Borough President Scott Stringer has been the most prominent among the contenders to become New York City's next fiscal chief. He's raised more than $3.5 million and spent about $566,000, city campaign finance records show, while his opponents have yet to report any fund-raising or spending.
They include Republican John Burnett, who has worked on Wall Street in various finance capacities and just recently declared his candidacy; Green Party candidate Juila Willebrand, a former teacher; and former madam Kristin Davis.
Spitzer is not the only politician who's looking for a second chance.
Former Rep. Anthony Weiner is running for mayor. The former Democratic congressman left office two years ago amid a scandal over his tweets.