Barcelona loanee Afellay sustained a tear at the junction of muscle and tendon in his right thigh. Therefore he will be out of action for at least two months. The 26-year-old Dutch international will undergo a rehabilitation programme to ensure a 100 percent recovery, reports Xinhua.
Moritz suffered a medial collateral ligament tear in his right knee during the 3-2 friendly win over Al-Saad. The German Under-21 midfielder will be sidelined for several weeks.
Both players will return to Germany Tuesday to start with the treatment.
Schalke sits currently at seventh position with 25 points, 12 points adrift from front-runners Bayern Munich.
The "Knappen" host Bayern Munich Tuesday for a test match in Doha.