Mayor Bill de Blasio sought Monday to “fill in those blanks” left by aides who struggled last week to defend his plan to restrict horse-drawn carriages to Central Park against aggressive questioning by City Council members.

He said several dozen carriage drivers stand to be affected by the proposed reduction of working horses to 75 from 180, but there would be “no job loss” because their union promised to find them employment in other fields.

At one point, drawing an asterisk in the air, de Blasio admitted that his team is still researching the logistics for a stable to be built in the park under the compromise between his office, Council Speaker Melissa Mark-Viverito and the Teamsters.

The revamp of an 86th Street building has an “initial estimate” of $20 million to $25 million in capital funds, de Blasio said.

“We think that is certainly a fair price to pay for a facility that needed to be upgraded anyway,” he said at a Manhattan event. He acknowledged later that the funds could go toward other administration priorities, but called the stable a “smart choice.”

De Blasio aides at a heated City Council hearing Friday couldn’t say exactly where the stable would be erected, how much the project would cost taxpayers, what park land might be sacrificed or how many carriage drivers’ jobs would be affected..

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“What you’re asking us to buy is an empty bag with a hole in it,” City Councilman Barry Grodenchik (D-Queens) had said.

De Blasio two years ago vowed an immediate end to the “inhumane” industry, but couldn’t gather enough support for a ban.

Teamsters Joint Council 16 spokesman Alex Moore confirmed the union had agreed to help ousted carriage drivers find jobs.

Also under the compromise, pedicab operators would be banned from working in Central Park’s southern sector, where tourists congregate and many carriage drivers are based. The pedicab operators are not unionized and did not have a say in the negotiation process. Dozens rallied at City Hall last week to say the mayor was effectively killing their industry.

De Blasio said that with 58.3 million tourists in the city last year, pedicabs are “going to have plenty of business. I don’t have a doubt in my mind.”

Though NYCLASS, the powerful animal welfare group that fueled the fight against the carriage industry with campaign donations, said it supports the compromise despite the lack of outright ban, other animal rights activists have not signed on.

Some park advocates have also opposed the bill, saying public land shouldn’t go to private use. The mayor said the stable would stand on land that’s currently inaccessible by the public.