Brandon has been under fire since he acknowledged that the athletic department made mistakes while dealing with quarterback Shane Morris' head injury during a loss to Minnesota in Ann Arbor.
"The systems failed, and there are a lot of issues we have to review," Ilitch told WWJ CBS-TV in Detroit.
The Wolverines also have struggled on the field under coach Brady Hoke, going 3-4 overall and 1-2 in the Big Ten this season.
The Board of Regents could influence any decision on Brandon, but it does not have the authority to fire him. That decision would have to come from new Michigan president Mark S. Schlissel, who took office July 1.
Sources told ESPN's Brett McMurphy that someone on Michigan's behalf has contacted three possible candidates to replace Brandon to gauge their interest in the job.
Michigan Students, Fans Protest Against AD
Joe Schad discusses the latest news from the University of Michigan, where students and fans demanded the school get rid of athletic director Dave Brandon.
Communication Breakdown At Michigan
Brad Edwards and Joey Galloway react to Michigan athletic director Dave Brandon's comments that the Wolverines' football program made mistakes because of a serious lack of communication while dealing with QB Shane Morris' head injury.