Sergio Aguero's first start at the Camp Nou for Barcelona ended prematurely when he was forced off the field after seemingly having difficulties breathing.
The Argentine, who left Manchester City for Barcelona as a free agent this summer, required medical attention shortly before halftime in the game against Alaves when he appeared to be experiencing breathing problems.
Barca's medical staff rushed on the pitch to assist Aguero and looked to place him on a stretcher, before he eventually got up and slowly walked off the pitch unaided.
The 33-year-old was replaced by Philippe Coutinho and subsequently taken to hospital for further assessments.