Chelsea goalkeeper Petr Cech is suffering from an elbow injury that will require surgery next summer, according to the Czech Republic's team doctor.
European champions Chelsea are hoping to manage Cech through the season and they have asked the Czech Republic to rest him from friendly internationals.
Czech national coach Michal Bilek has agreed to Chelsea's request.
"An investigation showed a bit of ossification in his elbow, so they (Chelsea) are planning a surgery in England after the season," Krejci told the Czech news agency CTK.
"They have asked us if we could rest him in friendly fixtures. We have come to an agreement with coach Michal Bilek and decided to be on good terms with Chelsea.
"We are going to grant their wish and rest him.
"Petr cannot stretch the arm properly. If he has to stretch the elbow, it hurts him sometimes.
"There is nothing to be worried about, though. There is basically nothing that could make this problem worse.
"The only thing that could force an immediate surgery is if the intensity of pain would get much higher or if the elbow was blocked in some way."
Cech captained the Czech Republic in Saturday's World Cup qualifier against Denmark in Copenhagen, which ended in a 0-0 draw, but he will sit out the Tuesday's friendly against Finland.