Michigan Football last year decided not to do a Spring Game. I'm pretty sure it was due to the weather but Harbaugh famously prefers to keep his opponents guessing. I did watch the ND spring game and they looked terrible, so maybe looking bad on tape is a good thing?
This year Michigan will be rolling out, somewhat of a new offense that Josh Gattis likes to call: Speed in Space. Michigan will only have two weeks of Spring Practice prior to the scrimmage, so I'm guessing we will see only a few changes.
The scrimmage is on April 13th at 5:00 and there will also be Fan Fest on April 6th.