The Premier League side have not enjoyed the best start to their domestic campaign.
As they prepare to take on Brighton in the Carabao Cup on Wednesday, O’Neil admits he may have to rotate his starting lineup.
He stated: “It’s a quick turnaround for us as well, from Sunday to Wednesday, I wouldn't have thought Daws would be able to play, Yerson (Mosquera) has had a couple of issues with his calves off the back of the Colombia game and did well to get through Sunday, Toti’s out, so we could be really short and we could see young lads at center-back at Brighton, because we have another really big Premier League game coming at the weekend.
“It’s a small hamstring issue for Toti who will be fit for Aston Villa, I'm not sure on Brighton, and Andre had a bit of cramp. He asked to come off as he was feeling cramp in his calf, which was similar to Nelson (Semedo).
“Rayan (Ait-Nouri) was another unfortunate one with his ankle injury, which we hope is not too serious because we’re going to need him. He rolled his ankle, the same one he rolled before, so he’s hopefully not too bad, but it’s too early to say. We’ve got quite a few issues to deal with for the Brighton game, so I would think it'll be a very changed team.”