Arturo Vidal faces an anxious wait for test results amid fears the Juventus midfielder will require knee surgery.
The Chile international has been struggling with a knee problem since the 2-0 defeat to Napoli and managed only a handful of substitute appearances.
He has been told to rest completely for three days before further tests and Tuttosport claim disappointing results will mean going under the knife.
Vidal and Chile are eager to avoid this solution, as it would rule him out for the rest of the season and leave him struggling for fitness going into the World Cup.
The operation would be keyhole surgery to clean up the meniscus ligament.