It's showed him on detached duty to Captain D.D. Porter who was in the 11TH TEX Cav. but Porter was captured in July 1864. That would be at the chattahoochee river before Sherman captured Atlanta.
David D. Porter was Assistant A.Q.M. (A.A.Q.M.) from October 15, 1862, at ranks of 1st Lieutenant and Captain. He was on Detached Duty from Company "E". He obtained clothing, forage and supplies for the Regiment until captured at Chattahoochie, Georgia on July 6, 1864. Sometime in 1863 he became known as the A.Q.M. for the regiment.