Former Scotland midfielder John Fleck was taken to hospital shortly before he was to take his place on the substitute’s bench for Chesterfield’s League Two game against Doncaster Rovers.
The treatment given to the 33-year-old at SMH Stadium meant the game’s kick-off was delayed by 10 minutes.
“We can confirm that John Fleck has been taken to hospital as a precautionary measure after being taken ill during the pre-match warm-up,” Chesterfield wrote on X.
Michael Jacobs replaced Fleck among the substitutes for the game against second-placed Doncaster.
The former Rangers and Sheffield United player joined the Spireites as a free agent in September after leaving Blackburn Rovers at the end of last season.
He joined Rovers from the Blades but suffered a shin injury 17 minutes into the derby game with Preston on his debut in February that required surgery.