Barcelona striker Sergio Aguero will be out for three months while he undergoes treatment for a suspected cardiovascular problem.

Aguero had to be substituted during the 1-1 LaLiga draw with Deportivo Alaves after feeling dizzy and suffering apparent discomfort in his chest.

The former Manchester City star was sent to hospital for a cardiac exam and will now not be available for Barca until at least February.

"The first team player Sergio Aguero has been subjected to a diagnostic and therapeutic process by Dr.Josep Brugada," A club statement confirmed. "He is unavailable for selection and during the next three months the effectiveness of treatment will be evaluated in order to determine his recovery process."

Aguero has only started two games since joining Barca after the end of his spectacular 10-year spell in the Premier League.

The Catalans face Dynamo Kiev on Wednesday (AEDT) in a key Champions League clash in Group E, in which they are third after three matches.