Ki has not played this season after picking up a knee injury on international duty, forcing him to undergo surgery, but boss Paul Clement says he is close to rejoining training.
Kyle Bartley (knee ligaments) and Dyer (Achilles) remain out, but Scotland Under-21 striker Oli McBurnie returns to the squad after his proposed loan switch to Barnsley fell through because the paperwork was not processed in time.
Meanwhile, Clement says Wilfried Bony is not ready to start and will begin on the bench at Wembley once more having played 21 minutes in last weekend's defeat to Newcastle before featuring for over an hour for the Under-23s on Monday.
"He played 63 minutes, scored a goal and showed his strength and leadership qualities. Now it’s about getting that match sharpness," said Clement.
"He was tired towards the end and was aching for a couple of days but it will not take him long because he is focused and motivated.
"If you think about what we do for pre-season, we give the players 45 minutes in the first game and build from there to 60 minutes and then a full 90, but all he has played is 60 minutes.
"We want him to make an impact off the bench initially and when he is ready we will put him in from the start.
"I haven’t decided for sure who will start on Saturday, to be honest. I think it’s more along the lines of unlikely."
Provisional squad: Fabianski, Naughton, Fernandez, Mawson, Olsson, Clucas, Fer, Carroll, Sanches, Ayew, Abraham, Nordfeldt, Rangel, Van der Hoorn, Britton, Mesa, Fulton, Narsingh, Routledge, Bony, McBurnie.