Luton's Premier League clash against Bournemouth was abandoned on Saturday after Hatters captain Tom Lockyer collapsed during the second half.
With the score level at 1-1 in the 65th minute, Lockyer suddenly fell to the turf in a worrying scene.
Play was paused as the Luton defender received treatment from medics while both sides were sent to the dressing room.
Lockyer was eventually stretchered off surrounded by the medical team.
There was a standing ovation from the crowd, with Luton fans in one corner of the Vitality Stadium chanting his name.
"There's a break in play as Tom Lockyer seeks medical attention. We are all with you, Locks," Luton said in a statement on X, formerly known as Twitter.
Reports emerged claiming that Lockyer was "alert and responsive".
Around half an hour after the incident, referee Simon Hooper confirmed the game would not restart on Saturday.
Players from both sides returned to the pitch and applauded the crowd.
Lockyer also collapsed during Luton's Championship play-off final win against Coventry at Wembley in May.
The Wales international was taken to hospital and later underwent heart surgery.
The 29-year-old had an operation to correct an atrial fibrillation, a condition the UK's National Health Service (NHS) describes as causing "an irregular and often abnormally fast heart rate".
