19-year-old Flood has also caught the eye for Asa Hartford's side and made his full debut last round's 7-1 hammering of Barnsley, before coming on during Sunday's 4-3 defeat at Newcastle.
Onuoha will play in his preferred centre-half role alongside skipper Sylvain Distin as Richard Dunne rests a sore groin. Meanwhile, D'Laryea replaces Steve McManaman in centre-mid, and Flood will go on the right to replace Shaun Wright-Phillips, who moves up front to partner Robbie Fowler.
Trevor Sinclair was unavailable for the Newcastle squad due to flu but may get a run out on the left after recovering, but Claudio Reyna, Joey Barton, Jon Macken, Nicolas Anelka, and McManaman are all injured.
Elsewhere, keeper Ronald Waterreus will replace David James, and has been told he will do as long as City remain in the Carling Cup.
"We will have four Academy kids in," Keegan confirmed in the M.E.N. "I have had to make changes.
"I have always played my strongest side whenever possible. But it gives me a chance to look at SWP with Fowler up front, and to look at the youngsters.
"Make no mistake, these kids are going to make it anyway. It just may be a little bit quicker than most people anticipated."