Chelsea boss Carlo Ancelotti has revealed Petr Cech suffered a calf injury in their Champions League defeat at Inter Milan.
Cech collapsed after leaping to make a catch during the second half of the first-leg match at the San Siro, and had to be substituted.
Reports had suggested the goalkeeper had suffered a serious knee injury, which would have meant a long lay-off, but the news from Ancelotti may prove positive for Chelsea.
Cech was replaced by Hilario after 61 minutes, and the reserve goalkeeper may now be thrust into a prominent role in Chelsea's pursuit of trophies at home and in Europe.
However Ancelotti is not ruling out the prospect of Cech making a swift recovery.
Asked about the severity of the injury, Ancelotti said on Sky Sports News: "We don't know now. We have to wait some days.
"We have to do a check control on his calf. We will take a decision and we will know how long he has to stay out."
As for whether Cech could feature against Manchester City in the Barclays Premier League on Saturday, Ancelotti added: "I don't know, we don't know, we have to wait."