I don't think you jumped the gun at all. Appears that they are not even selling seats on that DL2014 flight. If they force you to a different flight time, you can request a refund since it would be a 2 hour schedule change.
I suspect the flight will be available eventually when it gets loaded. Right now, the system is showing no flights at all between DTW and MKE on 1/6 which obviously has to change.