The union expected to send out ballots this week, the e-mail said.
Teachers have worked under five contract extensions since their collective-bargaining agreement expired in August.
PFT spokeswoman Barbara Goodman said that members would be briefed once an agreement has been reached.
"We would like our membership to know before they go into work [today]," she said.
Since negotiations began, disputes over key issues have slowed progress between a historically powerful union and an administration seeking to uproot tradition with controversial proposals.
Some of them include merit pay for teachers based on student performance, a longer school day and year, and the end of seniority-based teacher assignments.
Publicly, representatives from both sides have been tight-lipped about the progress of contract negotiations.
But Superintendent Arlene Ackerman has often said that the district's proposals can further her five-year reform plan, which has already led to reduced class sizes in earlier grades and an increased number of teachers and counselors in some schools.
Union officials have bemoaned what they said is the district's plan to diminish teachers' control.