Bill,
Your soldier was in Company A of the 10th Michigan Cavalry as:

Antoine Troutier

Residence was not listed; 25 years old.

Enlisted on 9/1/1863 at Muskegon, MI as a Private.

On 9/2/1863 he mustered into "A" Co. MI 10th Cavalry
He deserted on 9/10/1863 at Grand Rapids, MI

(The above information is taken from H.D.S. online database).

You'll probably want to get his compiled military service file and his pension records in order to investigate the circumstances of the desertion charge. But at least you'll now know which name to ask for and of which regiment. Good Luck, George Wilkinson