Illinois defensive coordinator Hardy Nickerson has resigned, citing personal health-related reasons.

Coach Lovie Smith said Monday that Nickerson told him it was in the program's "best interest" to leave the staff. The former NFL linebacker had been defensive coordinator and linebackers coach for more than two seasons after joining Smith and the Illini in 2016.

In a statement provided by Illinois, Nickerson said he had to step down now "due to health-related circumstances beyond my control."

The Illini (3-5, 1-4) have given up 158 points during a three-game losing streak, hurt by big plays despite a defense that had returned eight starters this season. Cornerbacks coach Donnie Abraham resigned less than three weeks before the season opener, saying he wanted to return home to Florida and spend time with family.