Barcelona striker Sergio Aguero was taken to hospital on Saturday evening after complaining of chest discomfort during the 1-1 draw with Alaves.
The 33-year-old was substituted shortly before half time at Camp Nou following several minutes of treatment on the field.
Aguero, who was making just his second start since joining Barca from Manchester City in the summer, was seen holding his chest as he made his way off the field.
The Catalan giants have now released a statement to confirm the Argentina international was admitted to hospital to undergo tests.
"Sergio Aguero reported chest discomfort and has been admitted to the hospital for a cardiac exam," the club statement read.
Barca remain ninth in La Liga, eight points behind leaders Real Madrid, after Luis Rioja struck to cancel out Memphis Depay's opener in the draw with Alaves.
No Data Analysis info
Germany
Switzerland
Hungary
Scotland
Spain
Italy
Croatia
Albania
England
Denmark
Slovenia
Serbia
Austria
France
Netherlands
Poland
Romania
Belgium
Slovakia
Ukraine
Portugal
Turkey
Georgia
Czech Republic