Before the star's heart problems are more carefully investigated, he is not up for play, the Spanish club states.
"Over the next three months, we will evaluate the progress of his treatment to determine how his recovery will continue," Barcelona said in a statement.
The 33-year-old was taken to hospital last Saturday after suffering from arrhythmia, disorders of the heart rhythm, during the league match against Alavés.
Agüero is said to have had chest pain for much of the first half and was replaced by Philippe Coutinho at half-time to be taken to hospital and a heart examination.