Chelsea boss Mauricio Pochettino concedes they've become too reliant on Cole Palmer.
The midfielder was missing for their 5-0 thrashing at Arsenal this week.
Pochettino said: "I think he's an excellent player for us, one of the key ones and that absence shows that without him we struggle a bit.
"This is the reality that we cannot hide."
He also said: "We have to be positive and we have to be strong and believe that tomorrow we can have a good game, a good attitude, a good approach.
"We will compete again with another team (Aston Villa) that is fighting for the top positions, but we are Chelsea and we must respect ourselves."
