At least 30 men are listed as "no further record" in regimental documents and with the exception of Henry Smith, Thomas Henfry and Virgil Hamilton all were listed in an "Unassigned" company.
Charles Brown, substitute
Joseph Cantor, substitute
Edward Grayson, substitute
John Hamilton, substitute
John Miller (2), substitute
William Monroe (2)
Edward New, substitute
John Otto, substitute
Henry Smith, substitute
Franz Sumner, substitute
Henry Ward, substitute
Charles White, substitute
Only Henfry and Hamill appear to have ended up in several different units: Henfry served in the 17th US infantry and Hamill served in the 12th Michigan infantry, the 1st US cavalry and in fact stayed in the army after the war serving out west for some years.
Eleven of the 30 were substitutes for men drafted.
Five of the 30 are known to have survived the war.
Enlisted in but never joined the regiment
Another seven men never joined the 3rd Michigan in Virginia: Rendel Fisher, William Sayles, Martin Bates, John Lucas, George Runyan, Edmund Bement and Preston Chaille. Aside from Fisher the other six joined a different Michigan unit: Sayles in the 6th cavalry, Bates in the 3rd cavalry, Lucas in the 10th cavalry, Runyan in the 5th infantry, Bement in the 12th infantry and Chaille in the Light Artillery. All but Fisher are known to have survived the war (what became of Fisher remains unknown).