Graham Potter believes Joao Felix's red card and subsequent three-match suspension is a "big blow" for Chelsea as they look to revive their disappointing Premier League campaign.
The Blues have won just one of their last nine league games following a 2-1 defeat at Fulham on Thursday night and also have injury issues.
Felix, 23, was fast-tracked into the side after signing on loan from Atletico Madrid on Wednesday and had looked to make an instant impact before his debut was cut short in the 58th minute.
Felix was sent off for a rash lunging tackle, despite impressing earlier in the match, and will face three matches on the sidelines.
On the suspension, Potter said: "Of course, (we are) disappointed because he came here to play, he's on loan to play.
"You saw his quality when he was on the pitch tonight, and then to lose him for the three games is a big blow for us but there's nothing we can do about it now, we have to just deal with it."
Denis Zakaria had just been forced off injured with a suspected quadricep injury before Felix saw red, taking the total list of Chelsea players unavailable to 11.
Reece James, Raheem Sterling, N'Golo Kante, Wesley Fofana, Ben Chilwell, Armando Broja, Reuben Loftus-Cheek, Christian Pulisic, Edouard Mendy and Zakaria are all out of the Blues' upcoming Premier League clash with Crystal Palace on Sunday.
Potter insisted the club are working to mitigate the injury crisis but admitted it is hard to find a solution.
"Absolutely, we're looking all the time and we're going over how they're happening and trying to evaluate the whole thing," the Chelsea boss said.
"Sometimes it's difficult when you come in halfway through the season, to know how they've happened, but I can sense it's a bit of bad luck and knowing how we can go forward and how we can improve."
He added: "The nature of them (the injuries), it's like there's not even a pattern, it's different problems, so it's tricky.
"It's not like we've been over training or anything like that, we just need to get to the bottom of it."
Chelsea have not lost at home to Crystal Palace since April 2017, but Potter believes there are a number of steps to be taken ahead of the match.
"We have to recover from the disappointment of the game tonight and then we have to assess all the players in terms of recovery and injury and then whatever we have.
"Then we have to try to be positive and move forward and take a home game on, another London derby against a team with dangerous players - so we have to be good and we have to prepare the team."
Crystal Palace boss Patrick Vieira feels his players must not be distracted by Chelsea’s current troubles as they look to address their own lack of consistency.
Palace are three points behind Chelsea, having played a match less, but come into Sunday’s game at Stamford Bridge on the back of successive defeats after crashing out of the FA Cup at home against Southampton last weekend.
While Chelsea boss Graham Potter may find his position under the spotlight and be dealing with a string of injury problems, Vieira insists there can be no sense of complacency within the Palace camp.
“The mood has been challenging, of course, because of the results that we have had, but I have seen a group who have been working well this week and waiting for the game to perform the best that we can,” the Palace manager said.
“We are looking at the squad that they (Chelsea) have and we are looking at the quality of the players that they have, we are looking at the quality of the manager that they have.”
Vieira told a press conference: “At the moment, yes, they may be in a difficult period, because things are going against them, but that doesn’t take away the quality that they have.
“We, again, have to perform well, and not think at all about the run of games they are having at the moment.
“We want to focus on ourselves. We want to improve regarding the last games that we played.
“We want to be more competitive, and more consistent in our performances, to allow ourselves to win games.”
Palace will have defender Tyrick Mitchell available again having served out a three-match suspension following a red card in the home defeat by Fulham on Boxing Day.
Vieira reported no other fresh selection worries as he plots Palace’s first Premier League win at Chelsea since April 2017.
Palace have been linked with a move for Club Brugge’s defensive midfielder Noah Mbamba, 18, and are also reported to be scouting for cover options at right-back.
“I always say we want to improve the squad and we know the profile that we want, then we just have to keep working and hopefully then we will bring in a couple of new faces,” Vieira said.
“We are looking at the squad we have. I always talk about the experience and the physical side of the game.
“We need more physical presence on the field, so these are the kind of profiles we have identified, that we have a lack of and want to improve.”
