My first thought was he was too disabled to serve in the Infantry but he joined up when General Forrest began recruiting in Tennessee.
Here are some NARA cards for the Regiment (from Fold3). These cards under the Unit Information would list the Officers and give an account of each one and then it gave a history of each company. Some regiments will have several detailed entries whereas other regiments will have a Card that simply states where they camped.
The 14 Tennessee has several cards giving a history for the Field and Staff (see header). The first companies have some history on a few cards. When you get to Company D---which was said to be Robert's company---it has several blank cards with just a record of where they were camped and all were in Virginia.
There was one card that is of interest.
First the Staff card that details where the regiment was mustered in.
It is strange that this is Dated 1864 in Virginia but it is describing the muster in Camp Duncan, Tennessee.
That is confusing.
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Now a card for Company D---the only one with any real info.
It is dated
1863 just prior to Gettysburg while there were at Culpepper Court House, VA. It starts out by saying we haven't had time to fill out muster roll because we were on the march all this time. (??)
They lost all their officers so maybe that explains why they lost their muster rolls and had to re-create them in 1864.
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