Aston Villa boss Alex McLeish believes his players will be trying to beat Chelsea on Saturday for captain Stiliyan Petrov.
The Bulgaria international, 32, developed a fever following last weekend's defeat to Arsenal and was diagnosed with acute leukaemia at lunchtime on Friday.
He is now in London for treatment which will begin immediately and McLeish voiced his shock concerning his well-respected skipper.
The Villa boss told Sky Sports News: "We certainly think it's in the early stages and Stan will get the best medical attention possible.
"I spoke to him about half an hour ago. He's typical Stan, defiant but I think obviously he's concerned about how it's affected his loved ones."
He added: "I knew he was getting more tests after the viral condition we thought it was last week when he had a temperature and reported to the doctor after the game on the bus journey back.
"And the doc told me yesterday that there's no chance of playing him, he was still run down and we were still waiting some results."
McLeish said he had not spoken to any of the players about the situation.
"The players will be gutted but hopefully galvanised to win this game for their captain tomorrow," he said.
"Stiliyan I'm sure he will be rooting for the lads tomorrow and sending some of the vibes for these boys to be inspirational for this game against Chelsea."
He added: "I know that some of the players are already texting each other and saying that kind of thing (this will be for Stan) to each other and I'm sure they'll be no doubt about that at all."