Chicago teachers union upbeat about possible deal (CBS/AP) CHICAGO - The Chicago Teachers Union president says a deal to end the city's first teachers' strike in 25 years is close, but she's pushed back her timeline a bit. Just hours after predicting students could be back in class by Friday, Karen Lewis said it might be Monday instead. She spoke to reporters Thursday morning on her way into negotiations. Negotiators say they made substantial progress the night before. Lewis says signing off on a final proposal would require a meeting by union delegates and that could take some time. Chicago teachers' strike grinds into third day Commentary: Chicago teachers strike - Give change a chance Chicago Teachers Union President Karen Lewis, right. The bargaining ended shortly before midnight Wednesday, and both sides agreed that they had got closer to a settlement. CBS station WBBM in Chicago reports Lewis came out smiling and saying she was happy. The optimism was echoed on the picket lines Thursday, four days after roughly 25,000 teachers went on strike and left nearly 400,000 students out of school. Lewis said the changes of getting a deal today were, on a scale of 1 to 10, a 9, WBBM reports. But the House of Delegates would still need to approve any agreement. "All parties need to just stay focused and get the best use of our time, " said Chicago School Board chief education adviser Barbara Byrd-Bennett Among one of the major concessions so far was the district softening its guidelines on a teacher evaluation system, which the union at first claimed focused too much on standardized testing. We feel like we're in a pretty good place. We've made a lot of progress today," Lewis said after talks ended Wednesday night, according to WBBM. We still have a lot of work to do, but it seems like we are definitely coming much closer together than we were, certainly this morning. Chicago School Board President David Vitale also said the talks were productive. He said both sides made headway on not only on teacher evaluation but on teacher recall - another issue the unions worried would leaved too many teachers laid off and without a job. "We had a very productive evening; really good discussion and proposals on the most difficult issues that we face," he said. I really think we shared a lot of back-and-forth on what really needs to get done to solve those most difficult issues. Byrd-Bennett said on WBBM Thursday that she wasn't happy with how talks started so late in the day Wednesday, but things ended on a good note. I was a little disappointed, initially, because I arrived at 11:15 and we didn't actually start a detailed conversation until 7:15 that evening. Nevertheless, the conversation was good," she said.