Sergio Aguero, a striker for Barcelona and Argentina, has been diagnosed with cardiac arrhythmia, a heart rhythm rate abnormality.
After only 40 minutes against Alaves, the striker, who was playing in only his second game with the Spanish giants, was hauled out due to breathing problems.
He was rushed to the hospital, where he was diagnosed with a cardiac condition following a series of tests.
Aguero had just recently recovered from a calf injury that had caused his debut to be postponed, and made his first appearance against Real Madrid on October 17.
Manchester City, a former club of the Argentine, were among the first to extend their best wishes to him.