The midfielder scored a goal in Sweden's first game against South Africa earlier this week. On Saturday, Annica Svensson will play in Fischer's place.
Fischer may be able to play again later in the Games, according to Staffan Stjernholm, a media officer with the Swedish Football Association.
"Nilla had an MRI yesterday. It's not a muscle or a tendon injury, rather she's strained her thigh. She could have played, but we don't want to take any chances" Stjernholm tells news agency TT.