Switzerland are hoping Philippe Senderos will not miss the rest of the World Cup after suffering an ankle injury against Spain.
Senderos, who agreed to join Fulham prior to the start of the finals, was forced off during Switzerland's historic success over Spain in the first half.
The centre-back picked up an ankle problem after colliding with a team-mate and he is heading to hospital for scans on the injury.
Speaking after the 1-0 win over the European champions, Switzerland coach Ottmar Hitzfeld expressed concern about the severity of the problem.
"Senderos has a sprained ankle and he may have a ruptured a ligament or worse," said Hitzfeld.
"He has to go to hospital to have some tests.
"It will be very difficult to replace him and it will be a major blow for my team if we were to lose him."
Steve von Bergen replaced Senderos against Spain and will be favourite to start Monday's game against Chile if his team-mate fails to recover.