Fellaini, who joined Shandong last January from the English Premier League side, returned to the country on Friday to join up with his club and tested positive for the coronavirus.
The former Belgium international did not have a fever and was asymptomatic, the club said, and has now been placed in quarantine.
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Chinese football has been hit hard by the outbreak, with the start of the Chinese Super League pushed back indefinitely from its intended Feb. 22 start date.
Fellaini, however, is the first player in the country's top flight to have returned a positive test for the virus.
Brazilian striker Dori, who plays for second division side Meizhou Hakka, was confirmed as having the virus last week while Spain-based China international Wu Lei said he was recovering from the condition on Saturday.
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