Sheffield Wednesday are braced for sanctions as the Football Association investigates allegations of missile throwing during the Steel City derby.
A coin and a plastic bottle were thrown from the crowd at Sheffield United defender Jack O'Connell during Monday night's goalless draw at Hillsborough.
Press Association Sport understands the incidents were included in referee Peter Bankes' official match report.
The objects were thrown from the stadium's north stand as O'Connell prepared to take a throw-in during the first half.
United boss Chris Wilder believes the derby atmosphere has turned particularly hostile in recent seasons.
"There were some coins – it's gone quite hostile," Wilder said in his post-match interview.
"It's always been boys and rough and tumble, but, when I was a player, you knew Sheffield Wednesday players and you used to go out and have a beer.
"It's gone pretty hostile now and I don't think anybody wants to see that. I'm disappointed it's gone that way and you can't really do a lot about it."
Wednesday manager Steve Bruce also condemned the incidents.
"If that is the case and somebody threw a coin then unfortunately it's the society we live in today and we'll find them and we'll deal with it," he said.