Villarreal defender Juan Manuel Pena has been ruled out for one month with a knee injury.
The Bolivian picked up the problem during Villarreal's 2-0 defeat to Deportivo La Coruna on Saturday, and had to be substituted after 33 minutes.
Doctors were quick to assess the injury and confirmed that it would take him four to five weeks to recover.
Pena's absence will be a massive blow to Villarreal, who have made a poor start to La Liga and are already missing three key players in Gonzalo Rodriguez, Pascal Cygan and Robert Pires.
Coach Manuel Pellegrini is not happy with his side's tally of one point from three games, but is believed to be on the look-out for reinforcements.
"The situation is not positive but we have to stay patient," he said.
Whilst Pena is out, Chilean midfielder Matias Fernandez is reportedly Pellegrini's number one target, with his club side Colo Colo claiming interest.
"We know the interest of Villarreal and are open to a deal," said Colo Colo president Christian Valera.
According to reports, Villarreal have already tabled an offer of é¼4 million (£2.7 million) for the 20-year-old and are awaiting a response.
Fernandez, born in Holland, is considered one of the best prospects in South America.