Obviously, the scheme change back to a 4-3 defense will affect the secondary less than the defensive line or linebackers, but KU is still going through some transition on the back end of the defense. The biggest hit was Karon Prunty leaving via the transfer portal; Prunty had a great freshman season last year and was expected to be one of the top corners in the Big 12 this fall. That one really, really hurts.
However, all is not lost. Kansas has some young talent that is expected to play early, as well as plenty of experienced players available.