MANHATTAN — The city wants to cut in half its pool of unwanted teachers — those who got kicked out of schools for disciplinary problems or because of enrollment drops — by paying half of their salaries from the school system's general pot of funds so individual schools don’t have to shoulder the costs from their own operating budgets as they try out these educators.

But if principals still have job openings after Oct. 15, the Department of Education will assign teachers to their schools — and can do so with or without a principal’s consent, under the program.

At that point, schools can't take advantage of the subsidy.

This is the second year of the subsidy that aims to reduce the number of teachers in the “Absent Teacher Reserve [ATR]” which currently stands at about 820, according to Department of Education data released Friday. But this is the first year the DOE is implementing the new program to force schools to take these teachers.

Last year, 372 such teachers were permanently hired at schools using incentives.

“We’re rethinking the ATR pool,” said Randy Asher, former principal of Brooklyn Tech who was appointed to tackle the thorny issue of these idle teachers and their swelling costs to the city.

For months, he has been talking with principals who have vacancies in attempts to help them find the best matches for their openings, he said.

"It's a constant process, and we've been in touch with them all through the spring," said Asher, who hopes to reduce the pool as much as possible before the Oct. 15 deadline.

The DOE also hopes to reduce its ATR pool through buyouts, offering a one-time payment of $50,000 or $35,000 plus six months of health benefits, for those who resign or retire this summer.

An analysis from the Independent Budget Office showed the city spent $151.6 million last school year on salaries and benefits for these teachers without permanent positions, according to Chalkbeat, which noted that it was more than the city planned to spend.

The average teacher in the ATR has been in the school system for roughly 18 years, earning about $94,000 annually. Many ended up ousted from their positions for different reasons: 38 percent came from schools that closed; 32 percent were there because of legal or disciplinary cases; and the other 30 percent landed there following a school’s budget reduction or enrollment loss, according to the DOE.

Nearly one out of five of these teachers were rated “ineffective,” “unsatisfactory” or “developing.”

Many principals have voiced concerns about the quality of these teachers, whether they were forced out because for disciplinary reasons or from failing schools that were shuttered. The fact that these teachers had yet to find positions on their own also raised red flags.

Teachers from the pool have always been placed in long- and short-term assignments, DOE officials noted, but now the department will work more closely with principals to place these teachers in schools that are unable to fill vacancies by Oct. 15.

Asher’s team is working hard to find the "right fit," he said, looking at each individual teacher and the vacancy, taking into account conversations with principals and superintendents, DOE officials explained.

“ATR teachers have always been in classrooms since the pool was started in the last administration, and now we’re taking a more strategic approach,” Asher said. "It's really a question of seeing where the needs are."

Teachers will be getting support from the schools, he added, and will be held accountable, too.

They would only remain at the schools if they received “highly effective” or “effective” ratings.

Many principals oppose the program, which they view as taking a bite out of their autonomy, and some said they will try to avoid revealing open jobs to the city’s hiring system past October, according to Chalkbeat.

"While many ATR teachers are able, this central mandate clearly puts budget concerns over principals' priorities even as the comptroller reports significant waste in other areas of DOE operations," said David Bloomfield, education professor at Brooklyn College and the CUNY Graduate Center. "The city is spending money hand over fist and needs to come up with an effective buyout offer instead of literally passing the buck to schools."

The teachers’ union defended the rank-and-file in the ATR pool, noting that teachers can end up there if schools or programs close or even if they had brief suspension from a "run-in" with their principal, said Michael Mulgrew, president of the United Federation of Teachers.

“They are a valuable resource for the system and provide needed services to schools, often filling in for teachers who are sick or on another form of leave," he said in a statement.

But Mulgrew also conceded that the ATR was “poorly designed” and never implemented effectively.

Charter school leaders admonished the DOE for spending so much on this pool of teachers.

“Spending more than $150 million to force bad teachers into classrooms is inexcusable, plain and simple,” Jeremiah Kittredge, CEO of Families for Excellent Schools, said in a statement.

He outlined some things the money could have covered, including the construction of two to six brand new schools, which cost roughly $66.5 million each; expanding a $47 million program bolstering mental health and alternative school discipline supports; and ensuring that every city student has free lunch, which would cost about $20 million a year.

Correction: An earlier version of this story incorrectly said the ATR was the "Rubber Room." Rubber Room teachers are those facing pending disciplinary charges. They can not be part of the ATR pool until their cases are resolved.