Obiang will be utilised in central midfield, allowing Manuel Lanzini to move into a more advanced position just off lone striker Javier Hernandez, who has shaken off a hamstring problem to feature from the off.
In terms of the visitors, manager Chris Hughton has been given a big boost with the news than centre-back Shane Duffy is fit to start after limping off with a groin strain in the 1-1 draw with Everton five days ago.
Brighton have won just one of their last seven league games away to West Ham, losing four of those.
West Ham United: Hart; Masuaku, Reid, Fonte, Zabaleta; Kouyate, Obiang; Arnautovic, Lanzini, Antonio; Hernandez
Subs: Cresswell, Adrian, Noble, Ayew, Ogbonna, Byram, Fernandes
Brighton & Hove Albion: Ryan; Bruno, Duffy, Dunk, Bong; Stephens, Propper; Knockaert, Izquierdo, Gross; Murray
Subs: Goldson, March, Schelotto, Krul, Suttner, Brown, Molumby