Huddersfield Town defender Tommy Smith is in a stable condition after he was taken by air ambulance to hospital with a head injury.
Smith suffered the injury while attempting to prevent Leeds striker Billy Sharp from scoring a late winner as his side lost 2-1 in the West Yorkshire derby with Leeds on Saturday.
He required lengthy treatment on the pitch before leaving the field on a stretcher wearing an oxygen mask.
Huddersfield subsequently released a statement on their official Twitter account, posting: "#htafc confirms Tommy Smith has been airlifted by Yorkshire Air Ambulance to Leeds General Infirmary for tests after suffering a head injury."
Later on Saturday a statement provided more encouraging news on his condition.
"Tommy became unconscious in the incident late in the game and was stretchered off after a lengthy period of treatment on the pitch," it read.
"In the medical room, his condition caused increased concern and after the full-time whistle, the Yorkshire Air Ambulance (YAA) was called. The YAA landed on the pitch at the John Smith's Stadium and Tommy was airlifted to Leeds General Infirmary.
"Tommy has subsequently undergone scans and tests and is now in a stable condition.
"We are pleased to report Tommy has been sitting up and talking to members of Huddersfield Town's staff who have visited him on Saturday evening.
"Tommy will stay overnight in Leeds General Infirmary for observation.
"Huddersfield Town and Tommy's family would like to thank everyone for their well wishes throughout the course of Saturday evening.
"Everyone at the Club would also like to record their thanks to all the medical team and safety staff on duty at the John Smith's Stadium, our charity partner the Yorkshire Air Ambulance and staff at Leeds General Infirmary for the care they have given Tommy.
"We all wish him a full and speedy recovery."