Schurrle picked up a leg muscle problem on international duty in midweek after scoring a hat-trick in Germany's 5-3 win over Sweden on Tuesday.
Mourinho has admitted that losing the winger is a blow to his short-term plans, but has refused to risk him against Cardiff with alternatives available.
He told the club's official website: "Schurrle is a kind of problem that happens a lot in a World Cup year.
"A player with a little problem wants to play in the national team and comes back to the club injured. We cannot risk him but again no problem.
"Of course he is in very good form but we have other options."
The 22-year-old has yet to net for Chelsea despite his scoring return to the international fold this week, drawing a blank in 10 appearances since his switch to Stamford Bridge.