This match has been postponed to play at a later date.
Burton Albion manager Nigel Clough says it was the "right decision" to call off their League One game at Barnsley after a man was taken ill before kick-off.
The match, which was due to get under way at 15:00 BST, was initially delayed while an air ambulance landed on the pitch, before later being postponed.
Clough told Burton's website: "Everyone hopes the gentleman is OK. In the scheme of it, football doesn't matter.
"Our players were not in the right mental condition to play the match."
Clough added: "When it was announced the game was called off, all the crowd were applauding respectfully as they realise it is the right decision.
"We also think it was definitely the right decision to call off the game. When you go out at 14:55, everyone is buzzing and right for the game - then something like this happens right where our players were doing their little bit of warm-up, they come in and naturally several were distressed.
"It was our lads who spotted what happened and who called the medical people over. They were right in front of it, as were our supporters. They knew something was wrong straight away.
"The referee and linesmen have all been brilliant about it and it's the right thing to do."
Barnsley issued a statement at around 17:30, thanking Yorkshire Ambulance service and both clubs' medical staff, as well as the fans.
The Tykes' safety officer, Steve Bailey, said: "It became apparent very quickly that the incident was of a serious nature.
"This required a quick response from all medical staff inside Oakwell at the time. We don't want to comment on the incident until we have further details.
"Football does not matter in a situation like this, we all send our best wishes to the gentleman and his family."
This match has been postponed to play at a later date.
Lineups are announced and players are warming up.