Marni Yang was to be sentenced Friday by Lake County Circuit Associate Judge Christopher Stride after being found guilty last month of the Oct. 4, 2007 murder of Rhoni Reuter and Reuter's unborn child.
During her trial, prosecutors painted the 43-year-old Yang as jealous of Reuter's relationship with Gayle, a member of the Bears 1985 Super Bowl team.
Prosecutors say attorneys on both sides are working to come up with a new sentencing date. No reason has been given for the postponement.
The Associated Press contributed to this report.