(CBS) – Chicago Public Schools officials say don’t worry about money this year. But the Chicago Teachers Union says not so fast.

The CPS budget proposes schools trim their bottom lines by more than $230 million, compared with the year before.

CBS 2’s Jeremy Ross reports on one assumption from bean counters that could lead to trouble.

“Today marks a return to financial stability for the coming school year,” CPS CEO Forrest Claypool, who promised no financial gimmicks, said Monday.

He said the district will not need to take out loans to keep school doors open next year — but adds part of the budget puzzle for 2017 relies on a piece that involves ongoing and sometimes contentious negotiations.

“Our starting basis for this budget assumes we will be able to reach an agreement with CTU,” Claypool said.

Chicago Teachers Union President Karen Lewis shot back, at her own news conference. “We have been bargaining in good faith since last year and we have yet to come to an agreement.”

One possible snag: CPS assumes the teachers union will pass a budget proposal that rank-and-file members voted down in January.

Lewis wasn’t afraid to talk about a strike during her news conference, but added: “Chicago teachers do not seek to go on strike. We want to return to clean safe, resourced schools.”

Claypool says the earlier proposal to teachers is a “good framework.”

The CPS system says it will hold a half dozen meetings to discuss the budget plan, which is slated for a vote Aug. 24.