Manchester United defender Victor Lindelf was struck by a missile during their FA Cup final defeat to Manchester City.
Lindelof was hit by a lighter as the players celebrated United's equaliser before halftime.
While on punditry duty for the BBC, Peter Schmeichel commented on the incident, saying: “That is so wrong. That's bad.
“I'm not blaming Manchester City - it is somebody - but we are at the Manchester City end, they were celebrating in front of the Manchester City supporters, and they should be big enough, they're winning enough, to understand it's okay to go 1-1.
“They shouldn't react like that. That is terrible, it should have consequences. I hope they find the guy, whoever did that."
Alan Shearer, also on the pundits panel, added: “We don't want to see that."