The Czech shot-stopper has torm his calf muscle and could be sidelined for several weeks.
"It's still early but it's almost certain he will miss the game this weekend," said club doctor Bryan English.
"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," he added.
Carlo Cudicini, who was a half-time sub for Cech in the awful 0-0 draw against Schlake 04 last night, will make his first league start of the season.