Chelsea will be without Petr Cech for Sunday's game against Everton after scans revealed the goalkeeper suffered a small tear in his calf muscle against Schalke.
The Czech Republic international was substituted at half-time during Tuesday's goalless draw in Germany and will be replaced by Carlo Cudicini for the weekend visit of the Merseysiders.
Cech is also expected to miss his country's forthcoming Euro 2008 qualifying double-header with Slovakia and Cyprus.
"It's still early but it's almost certain he will miss the game this weekend," Chelsea club doctor Bryan English told the club's official website.
"We will also be liaising with the Czech FA's medical department about Petr's injury. Hopefully the international break will allow time for the injury to improve."
Cech himself added: 'I don't know exactly how it happened. I only know that I felt a pain from the tenth minute of the match.
"Nevertheless I played the first half. I feel bad that I will be out right now when myself as well as my team are both doing well."