Chicago Teachers Union President Karen Lewis said "I'm a 9" on a scale of 1-to-10 on a deal being reached soon, but she said classes could not resume until Monday because any tentative deal ending the walkout would have to be approved by the union's 700-member House of Delegates.
The House of Delegates scheduled a meeting for 2 p.m. Friday afternoon after significant progress was reported in contract talks between the school board and striking public school teachers, the Chicago Tribune said.
If a contract is accepted by the delegates it would then have to be formally approved by 26,000 rank-and-file union members, which could take up to a week or more.
"We're hoping we can tighten up some things we talked about yesterday ... and get this thing done," Lewis said.
The teachers also scheduled a noon rally Saturday as striking teachers continued to picket on the sidewalk outside the Chicago Board of Education headquarters.
Earlier, Chicago school board president David Vitale said he was hopeful the city's 350,000 public school students could return to class by Friday, the Tribune said.
Public school officials presented a revised contract proposal to the union Tuesday.
Lewis said the two sides were coming closer on an agreement about teacher evaluations, which has been a key stumbling block, the Chicago Sun-Times reported. While not ready to check it off her list, "it's a lot better," Lewis said.
Students have been out of school since Monday.
The district proposal softens an evaluation system demanded by Mayor Rahm Emanuel that the union said could put nearly 30 percent of public school teachers on the path to dismissal if performance didn't improve within a year, the Sun-Times said.
Emanuel has called for teacher performance to be evaluated in part on the results of standardized tests. The union says the tests don't take into account socioeconomic differences among students in vastly different neighborhoods.
Another key issue involved rehiring teachers laid off from schools that get shut down or shaken up.
The proposal made public Wednesday would let teachers vulnerable to dismissal stay at their jobs indefinitely, provided the test scores didn't dramatically decline after the first poor score.