Deportivo La Coruna have been rocked by the news that Sergio could be out for a couple of months.
The midfielder has undergone scans to determine the extent of a ruptured muscle in his leg and he is now set for a spell on the sidelines.
It is thought that if he tries to return too quickly there is a risk of more serious damage and coach Miguel Angel Lotina is unlikely to be able to call on his services much before the end of the season.
Lotina has already lost several key men to injury and admits it will be even more difficult without Sergio
"This is a blow because now we are playing the decisive moments in our season with a reduced amount of players available to us," he said.