Graham Potter promised Chelsea are doing what they can to get to the bottom of their injury issues.
Chelsea lost a third successive game on Thursday as they went down 2-1 to Fulham in a west London derby.
Compounding their issues at Craven Cottage, where debutant Joao Felix was sent off, midfielder Denis Zakaria suffered a quad injury.
It means Zakaria joins Raheem Sterling, Christian Pulisic, Edouard Mendy, Armando Broja, Ruben Loftus-Cheek, N'Golo Kante, Reece James, Ben Chilwell and Wesley Fofana on the sidelines.
Ahead of Sunday's clash with Crystal Palace, Potter – who has seen his side lose seven of their last 10 matches – knows Chelsea must find a solution.
"We're looking all the time, going over how it's happening," said Potter, who replaced Thomas Tuchel in September.
"Sometimes when you come in through the season it's difficult to know how it's happened. It's a bit of bad luck and also learning for us all how we can improve.
"The nature [of the injuries], it's not even a pattern, it's different problems. It's tricky.
"It's not like we’ve been over-training or anything like that. We certainly need to get to the bottom of it though."
Joao Felix's three-match suspension, meanwhile, has dealt another blow.
"Of course, disappointing because he came here to play, he's on loan to play," Potter said.
"You saw his quality when he was on the pitch and to lose him for the three games is a real blow for us. Nothing we can do now, we've just got to deal with it."
Chelsea are rooted in 10th place in the Premier League, and Palace would move level on points with the Blues should they win.
Potter has never won a home game against Palace across his managerial career, drawing one and losing three of four previous such games in charge of Swansea City and Brighton and Hove Albion, though Chelsea did beat the Eagles 2-1 at Selhurst Park under his stewardship earlier this season.
Chelsea have won their last 10 league games against Palace but have lost two of their last three top-flight matches at Stamford Bridge, and Potter knows his team need to get back to their best.
"We have to recover from the disappointment of the [Fulham] game, assess all the players and then we have to try to be positive, take a home game on, another London derby against a team with dangerous players, so we have to be good ourselves," he said.
Potter, meanwhile, confirmed there is no chance that Pulisic, who is set to be out until March due to a knee injury, will leave the club in January.
"No chance," he said. "There's never been any consideration about that anyway but he's a couple of months out.
"He's disappointed, optimistic he can come back quicker than the two months, so it's at that stage where it's fingers crossed for his rehab."