Aston Villa's Swedish goalkeeper Robin Olsen was attacked as Manchester City fans celebrated their Premier League title win by invading the pitch at the Etihad Stadium on Sunday, with the club launching an investigation into the incident.
City beat Villa 3-2 to secure the league title, prompting fans to pour on to the field.
Asked whether his players were able to get off the field safely, Villa manager Steven Gerrard said: "My goalkeeper was attacked. So I think those questions should go to Pep (Guardiola) and Manchester City... We're going to check on him," he said.
City issued a statement shortly after the trophy had been presented to their team, saying: "Manchester City would like to sincerely apologise to Aston Villa goalkeeper Robin Olsen, who was assaulted after the final whistle at today’s match when fans entered the pitch.
"The Club has launched an immediate investigation and, once identified, the individual responsible will be issued with an indefinite stadium ban."
The incident follows others in end-of-season games in England, including a clash between Crystal Palace manager Patrick Vieira and an Everton supporter on Thursday.