AP

Mike Martz is done in Chicago.

Martz has resigned as offensive coordinator of the Bears, citing philosophical differences, Dan Pompei of the Chicago Tribune reports.

It’s not clear what those philosophical differences are, and whether they’re with head coach Lovie Smith, or with the direction the team’s personnel department will go in now that G.M. Jerry Angelo has been fired.

Vaughn McClure of the Chicago Tribune reports that quarterbacks coach Shane Day is out as well. Day was hired at the same time as Martz, who has spent the last two seasons as offensive coordinator of the Bears. Martz was previously offensive coordinator in San Francisco, Detroit and St. Louis, as well as head coach of the Rams.

Now Smith will need to find an offensive coordinator who has a plan in place to build an offense that can succeed with quarterback Jay Cutler — and, Bears fans hope, an improved supporting cast around Cutler. That could mean promoting offensive line coach Mike Tice to the coordinator position, or it could mean completely revamping the offense by bringing in someone from the outside.