According to University rules the only thing that would result in a 4 game suspension (and would therefore be beyond the control of Kelly) would be:
Second Positive Test for Marijuana-
- ban from intercollegiate competition for 33% of championship segment
- probation for 1 year
That said, there is an appeals process and it is not exactly clear if results of testing administered by entities other than ND or NCAA can be used to sanction an athlete.