Kehrer was missing from the matchday squad for Sunday's 3-1 victory over Chelsea but is due to return to training this week ahead of Saturday evening's trip to the south coast.
Kehrer's return will give David Moyes pptions in defence, with the German providing competition for Vladimir Coufal at right-back or capable of slotting into a back-three, should the Scot wish to strengthen his backline against Roberto De Zerbi's free-scoring side, who have found the net eight times in two matches already this term.
However, he will have to do so without Nayef Aguerd who is suspended for the game.
The Hammers are expected to complete a £20million deal to sign Stuttgart defender Konstantinos Mavrpoanos within the next 24 hours after the Greek international underwent a medical in east London over the weekend.
Mavropanos, who was at the London Stadium for the win over Chelsea, will become the Irons' third summer signing, following midfielders James Ward-Prowse and Edson Alvarez, who both made debuts against the Blues.