Barcelona have confirmed striker Sergio Aguero will miss at least three months of football with a heart problem after undergoing tests.
The Argentina international was taken off before half time in Saturday's draw with Alaves, having received treatment for several minutes after suffering with chest pains.
He left Camp Nou by ambulance and underwent cardiac tests at hospital. He was diagnosed with cardiac arrhythmia - an irregular heartbeat - but Barça have now confirmed their summer signing will be under observation and won't play for the remainder of the year.
Their statement reads: "The first team player Sergio Aguero has been subjected to a diagnostic and therapeutic process by Dr.Josep Brugada. 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 had a wretched time since leaving Manchester City upon the expiry of his contract and moving to Camp Nou.
He had hoped to play alongside childhood friend Lionel Messi, but the club's dire financial state meant the Barça legend was forced to leave before they could take the field together at club level.
Aguero was then ruled out for ten weeks with a strained tendon in his right calf and only made his official debut for La Blaugrana when he came on as a substitute against Valencia in mid October.
The former City striker continued to make sub appearances, scoring his first goal for the club in the 2-1 Clasico defeat to Real Madrid before starting the 1-0 defeat to Rayo Vallecano.
His old club have sent their best wishes to the 33-year-old, while Raheem Sterling tweeted: "Stay strong my brother , we’re all with you. Get well soon."