The hole in the bark is fairly old damage.  Could there have been some mechanical damage to this tree at one point?  Also, if you look at the base near the soil line there is some damage that could be (also older) from rotting (phytopthera root rot) or perhaps a string trimmer.  If there is a rot fungi, you may see splitting of bark above that area that peels away easily with some gentle probing with a screwdriver.  If you value this tree, you may wish to contact a certified arborist to come do some additional investigation.  Look at the Michigan Certified Arborist list to find one close to you.  Thanks for your question.