Chicago Teachers Union President Karen Lewis encouraged members on Monday to "save at least 25 percent of their pay in preparation for a possible strike."

Lewis made that recommendation upon learning that teachers "could start losing their jobs as early as January" as part of a massive round of layoffs that could occur if the district does not get the $480 million in pension savings it is seeking from Springfield. 

"With the uncertainty in Springfield, the continued chaos at the Board of Education, and the constant threats to our classrooms, we have to be prepared," Lewis said in a news release. "Our families will depend on us being able to weather what could be a protracted strike."

CTU announced Monday that it will hold a "'practice' strike vote and contract poll in all CPS school buildings" on Thursday. In order to strike, the CTU would need authorization from 75 percent of its members.

The union also plans to hold a rally in Grant Park on November 23.

CTU's contract with the school district expired on June 30. The two sides are in contract mediation and "negotiations are ongoing," according to the union.