Waldroup, J S
Private—Enlisted at Bright Star, Arkansas, March 6, 1862; age 25 age 34; captured at Champion’s Hill, Mississippi, May 16, 1863; sent to Fort Delaware, September 22, 1863; exchanged, November 1, 1863

This soldier was in Company K which was raised in Lafayette County and is most likely the same man. Don't know what's up with the double age, but 25 would be correct for your guy.