Chelsea boss Roberto Di Matteo admits Gary Cahill's fitness remains a cause of concern as the Blues count down the days to their meeting with Bayern Munich in the UEFA Champions League final.
Chelsea booked their place in European football's showpiece event with a battling, 10-man display against Barcelona on Tuesday.
A 2-2 draw at Camp Nou, and a 3-2 victory on aggregate, came at a price, though, with untimely injuries and suspensions picked up.
Among those to be laid low was centre-half Cahill, who claims to have felt something 'pop' in the back of his thigh.
He lasted just 12 minutes in Catalunya and scans carried out since his return to England have confirmed that he has suffered serious damage to his hamstring.
Chelsea, who will without banned captain John Terry against Bayern, are still hoping that Cahill will be ready to play some part at the Allianz Arena, but Di Matteo admits the England international faces a race against time to prove his fitness.
"We hope, and we will try, to get him back fit as soon as possible," he said.
"But at the moment it's difficult to put a date on it. It's too early to clarify that.
"We'll have to see how his injury improves on a daily basis.
"At the moment all we can say is we hope that he'll recover as quickly as possible. That's our hope and our aim. When he's going to be fit, we can't say."