Karen Curley ran into something surprising as she headed into her Park Slope gym on Wednesday: protesters pushing back against the city’s strategy to give her a job.

Curley, 61, a Department of Education social worker who used to work in District 17, has been rotating through different positions for at least two years. She is a member of the Absent Teacher Reserve, the pool of teachers without permanent assignments that is once again at the center of debate over how the city should manage teachers and spend money.

The protesters had gathered outside the Prospect Park YMCA to confront its most famous member, Mayor Bill de Blasio, about the city’s plans to place roughly 400 teachers from the ATR into school vacancies come October. They say the city is going back on an earlier vow not to force the teachers into schools.

“These are unwanted teachers. There’s a reason why they’re just sitting there,” said Nicole Thomas, a Brooklyn parent and volunteer with StudentsFirstNY, an advocacy group that organized the protest and often opposes the mayor. “We don’t want these teachers in our schools.”

In fact, the ATR pool includes both teachers whose positions were eliminated because of budget cuts or enrollment changes, and also teachers who have disciplinary records. The city has not disclosed how many teachers in the pool fall into each camp, or which ones will be assigned to positions this fall.

Curley said she was heartbroken when she realized the protest was directed against the Absent Teacher Reserve. “We don’t want to be absent,” she said. “We’re educators.”

She said cost was likely an impediment to their hiring. “The truth is, at this point, I have 20 years in [the school system], which isn’t a lot for someone my age,” she said. But after 20 years, “we’re not likely to be hired elsewhere because we’re high enough on the pay scale that new people can be hired for a lot less money.”

Earlier Wednesday, Chalkbeat cited new figures from the Independent Budget Office placing the cost of the Absent Teacher Reserve at $151.6 million last school year, an average of roughly $116,000 per teacher in salary and benefits. Some principals have balked at the idea of having staffers forced on them in October — and vowed to avoid having vacancies.

Shortly after 10 a.m., the mayor emerged from the gym and hurried into a waiting car without addressing the protesters, who chanted, “Hey hey, ho ho, forced placement has got to go.”

Thomas was disappointed he didn’t stop. “He didn’t even acknowledge us,” she said. “And we voted for him.”