Kodjia limped off after just 36 minutes at the Pirelli Stadium but was back in training late this week and is clear to lead the line against the promotion-chasing Royals.
Hourihane's inclusion in the middle of the park alongside Henri Lansbury, Albert Adomah, Mile Jedinak and Leandro Bacuna means that Jordan Amavi drops down into the back four, where he is joined by Alan Hutton, James Chester and Nathan Baker.
For the visitors, Jaap Stam makes four changes following the side's 7-1 humiliation at Norwich City last weekend.
Joseph Mendes comes into the side at the expense of Yann Kermorgant and partners Lewis Grabban up front, while Danny Williams and Adrian Popa come into the midfield alongside Liam Kelly and John Swift, with Garath McCleary and Jordon Mutch demoted to the bench.
Aston Villa: Johnstone; Hutton, Chester, Baker, Amavi; Adomah, Lansbury, Jedinak, Bacuna, Hourihane; Kodjia
Subs: Sarkic, Richards, Elphick, Hogan, Bree, Gardner, Grealish
Reading: Al-Habsi; Gunter, Moore, Blackett, Obita; Swift, Williams, Kelly, Popa; Mendes, Grabban
Subs: Jaakkola, Evans, McCleary, Kermorgant, Meite, Ilori, Mutch