Leicester boss Craig Shakespeare will refuse to gamble on Wes Morgan's fitness to keep their Champions League dream alive.
The skipper is definitely sidelined for Saturday's Premier League trip to Crystal Palace with the back injury which has seen him miss the last five matches.
The Foxes host Atletico Madrid in Tuesday's quarter-final second leg, having lost 1-0 in Spain on Wednesday, with Robert Huth banned and Yohan Benalouane their only available centre-back.
But despite his defensive issues Shakespeare is not prepared to risk centre-back Morgan if he fails to prove his fitness.
He said: "We'll only put him in if he's ready. The conversation will be with Wes and our medical department and we'll give him every opportunity between now and then but if he's not ready we won't take a gamble.
"He's trained yesterday, not all with the squad, but I have said before it will be 50-50 for Atletico Madrid. He won't feature against Palace.
"I haven't seen the players this morning but I need to assess them all. We only had a light training session on Thursday for the players who played and a full session for those who didn't."
And Shakespeare is prepared to rest and rotate players at Selhurst Park with midfielder Daniel Amartey, who was in the African Nations Cup team of the tournament after playing for Ghana at centre-back, possibly playing in defence.
He said: "If I think it's the right thing to do and benefits the team all players are adaptable. Of course they have their preferred position but there are players within the squad who can utilise different positions and Daniel is one."
Leicester go to Palace having lost their last two games - following six straight wins - with the Eagles having won five of their last six outings.
Shakespeare worked with Palace boss Sam Allardyce during Allardyce's 67 days as England manager.
The 53-year-old was appointed as a coach and spent 10 days in the Three Lions set up and was on the bench for September's 1-0 World Cup qualifier in Slovakia.
Allardyce left the England job at the end of September when he was caught in aftermath of an undercover newspaper investigation but Shakespeare is pleased with his revival at Palace.
He added: "Having worked with Sam in a very short space of time his record there is for all to see. He's never been relegated from the Premier League. Having seen him work at close quarters, how diligent he is on the opposition it doesn't surprise me."