Sergio Aguero ruled out of last-16 tie against Switzerland

Argentina forward Sergio Aguero has been ruled out of the World Cup last-16 tie against Switzerland due to a hamstring injury.

Reports had suggested that the muscle problem he picked up in the victory over Nigeria would be enough to end his participation in the tournament, but Argentina are refusing to confirm whether the Manchester City striker will be able to return if they progress past the Swiss.

"It's a first-degree muscle strain in his femoral biceps," team doctor Daniel Martinez said in Thursday's press conference. "It's a degree lower within the muscular injuries. He will try to recover as soon as possible.

"The recovery already started on Wednesday. From Switzerland onwards, it will depend on whether Argentina remains in the competition and on his day-to-day recovery in order to see him back on the pitch."

Argentina qualified as winners of Group F with three wins from three games.