Boston Mayor Marty Walsh on Friday pushed back against the notion that he violated an agreement with the Boston Teachers Union regarding a decision made this week to postpone the next phase of in-person learning, but still require some teachers to work on-site.

After the COVID-19 positivity rate rose to 4.1% in Boston earlier this week, Walsh announced on Wednesday that phased reopening of in-person learning would be pushed back from the scheduled Oct. 15 date to Oct. 22. But some teachers, he said, would still be required to go to school buildings to educate Boston's "highest-need" students, including those with disabilities, English language learners, and those experiencing homelessness.

BTU has sued city and school officials, arguing the decision violates an agreement between the city and the union that would shut down school completely and give teachers the opportunity to work remotely if the positivity rate tops 4%.

"If the citywide COVID-19 positivity rate rises above 4% citywide, BPS will transition to full remote learning for all students, and BTU bargaining unit members will have the option to be remote as well. When the Boston Public Health Commission or other City or State authority determines that the school district can reopen, BTU bargaining unit members will be expected to return to BPS buildings," the agreement reads.

When asked during an interview on Boston Public Radio whether his decision violates that agreement, Walsh responded, "No, not necessarily."

Walsh cited language in the agreement that states that public health officials can determine when the school district can reopen, at which time union members would be expected to return to BPS buildings. He said public health officials have determined that in-person learning can continue for the roughly 1,300 students per day that are currently in schools, averaging about 10 students per school, he said.

"We're talking about 10 students in a school that would have hundreds of kids in them that we can protect safely, not only educate and provide services to students that need it the most, but also make sure our teachers are safe as well while they're in the building," he said.

The union asked for an injunction that would give educators the choice over whether to continue showing up to school buildings, rather than mandate it, or work remotely.

BTU President Jessica Tang said Thursday the union wants to ensure in-person services for highest-need students, but "need a plan for it."