Illinois defensive coordinator Hardy Nickerson is on leave from the team after the unexpected death of his mother Sunday night.
Coach Lovie Smith said Monday that Nickerson was on his way home to California. There is no timetable for his return.
Illinois (2-7, 0-6 Big Ten) will host Indiana (3-6, 0-6) on Saturday. The Hoosiers are ranked eighth in the Big Ten with an average of 25.9 points per game.
Smith said he hasn't addressed who will provide the defensive game plan in case Nickerson is absent.
Smith, who is a former NFL defensive coordinator and head coach, said: "I have called a couple defensive games, and know a little bit about defensive football, so we may be OK."