Chelsea's goalkeeper Petr Cech (C) challenges Inter Milan's Samuel Eto'o (L) as Michael Ballack watches during their Champions League soccer match at the San Siro stadium in Milan February 24, 2010.

Chelsea manager Carlo Ancelotti revealed Petr Cech sustained a calf injury in the Champions League defeat by 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, English news agency Press Association reported.

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."