Media reports initially said Xhaka had been taken to hospital after colliding with team mate Valon Behrami during a practice session held in pouring rain.
However, the Swiss football federation (SFV) said the Arsenal player had visited a clinic only to undergo a MRI scan.
Xhaka is a key player for Switzerland who face Brazil, Serbia and Costa Rica in World Cup Group E.
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"I am very relieved," said Xhaka who sadi he regretted the fact that the speculation had left his family worried.
"We could establish that the ligaments were intact, but we wanted to play it safe," said Switzerland team doctor Pierre Etienne Fournier. "It's just a painful bruise on the knee."
The SFV said that Xhaka would miss Sunday's friendly away to Spain as well as several training sessions. (Writing by Brian Homewood in Bern; Editing by Ken Ferris)
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