Motherwell captain Phil O'Donnell has died after collapsing towards the end of his side's Scottish Premier League game against Dundee United.
O'Donnell collapsed during the game against Dundee United
The 35-year-old midfielder fell to the ground just as he was about to be replaced with Marc Fitzpatrick near the end of Motherwell's 5-3 victory.
O'Donnell was treated for around five minutes on the field before being taken to a waiting ambulance.
But his death was later confirmed by the Fir Park club.
Motherwell chief executive Ian Stillie said: "The management, directors, players and fans are all stunned and having great difficulty in comprehending what has happened over the last few hours.
"At this stage, we do not have all the facts surrounding the tragic death of Phil O'Donnell.
Phil was a great professional and gave everything when he played the game
Motherwell manager Mark McGhee
"We have been in contact with Phil's wife, Eileen, and his family and they have given us their blessing to speak to the media.
"Phil collapsed during the second-half of the game. He was standing alone at the time.
"He was immediately attended to by Motherwell's club doctor and assisted by Dundee United's club doctor.
"He was transferred almost immediately to an awaiting ambulance and taken to Wishaw General.
"It is believed Phil suffered some form of seizure and was pronounced dead at 1718."
PHIL O'DONNELL'S CAREER
1972 - born in Hamilton
1991 - joins Motherwell
1991 - scores in Scottish Cup final victory over Dundee United
1993 - earns only Scotland cap against Switzerland
1994 - sold to Celtic for a club record £1.75m
1999 - signs for Sheffield Wednesday
2003 - released after injury-hit spell at Wednesday
2004 - returns to Motherwell, becoming club captain
O'Donnell, who earned one cap for Scotland, was lauded as one of the country's brightest talents when he broke into the Motherwell first team as a teenager.
He moved on to Celtic for a club record £1.75m fee, but injury problems were to blight his time there and at his next destination, Sheffield Wednesday.
O'Donnell returned to Motherwell in 2004 and became club captain, playing alongside his nephew, David Clarkson.
Motherwell owner John Boyle said: "Everyone at Motherwell is shocked to the core and we are sure that everyone involved in Scottish football will feel the same.
"Phil was not only an inspirational player for Motherwell and club captain but was an inspirational person."
Motherwell manager Mark McGhee had said immediately after the game that O'Donnell's substitution had been "an absolute coincidence" before his sudden seizure.
The manager had simply been looking to give his captain a rest ahead of Wednesday's game against Hibernian, which has been postponed in light of the player's death.
Clarkson, who had scored two of Motherwell's goals, was substituted moments after O'Donnell's collapse.
"We took Clarkson off because he got a fright from the nature of the collapse," said McGhee.
"We are all totally devastated. This is a shocking tragedy."
Motherwell striker Chris Porter added: "His number had come up for him to go off and he literally just passed out.
"He went down and no-one really knew what had happened.
"Doctors and physios ran on, he was unconscious on the floor and it was clear he was in a bad way, but personally I never thought anything would happen.
"Everyone thought he would be okay and he had just fainted, so it was a real shock to find out he had passed away."