Hernandez comes in for Helder Costa who drops to the bench while Berardi replaces skipper Liam Cooper who is back from a hamstring injury but only amongst the substitutes.
Gjanni Alioski also returns to the bench following a side injury and takes the place of Leif Davis.
Former Whites loanee Izzy Brown has been passed fit after a hamstring injury and starts for the Hatters.
Luton Town: Shea, Potts, Tunnicliffe, Bradley, Pearson, Shinnie, Mpanzu, Bree, Brown, Cornick, Collins. Subs: McManaman, Sluga, Bolton, Galloway, LuaLua, Jones, Butterfield.
Leeds United: Casilla, Ayling, White, Berardi, Dallas, Phillips, Klich, Hernandez, Harrison, Roberts, Bamford. Subs: Meslier, Douglas, Cooper, Alioski, Costa, Gotts, Clarke.
Referee: John Brooks.