A man has been arrested on suspicion of assault after Sheffield United captain Billy Sharp was knocked to the ground following a pitch invasion after their Championship semifinal playoff defeat to Nottingham Forest on Tuesday night.
Footage after the match appeared to show Sharp being charged at following a pitch invasion.
Chief Inspector Paul Hennessy, of Nottinghamshire Police, said: "A 31-year-old man has been arrested on suspicion of assault in connection with this incident. He remains in custody and will be questioned by officers.
"Our enquiries into the circumstances surrounding the incident are ongoing. We have spoken to the player concerned and we are working with both clubs who are supporting us with our investigation."
Sheffield United manager Paul Heckingbottom said: "We've seen one of our players attacked.
"He's shook up, bleeding, angry. Bill was minding his own business off the pitch, trying to get our players away. He was blindsided, it was cowardly. He was knocked to the ground [and required] stitches, he was shook up."
A Nottingham Forest statement said: "Nottingham Forest Football Club are appalled to learn that our former player, Billy Sharp, was assaulted leaving the pitch after tonight's match at The City Ground.
"The club will work with the authorities to locate the individual in order they are held to account for their actions, which will include a life ban from Nottingham Forest.
"The club would also like to apologise to Billy personally and to Sheffield United Football Club."
Sharp did not play in the match as he was ruled out through injury. The 36-year-old is in his third spell at Sheffield United, and also spent time on loan at Nottingham Forest in 2012-13.
In a statement released on his Instagram Wednesday, Sharp further condemned the incident.
"One mindless idiot ruined what was an unbelievable night of football," he said.
"Congratulations to Nottingham Forest on their victory and good luck in the final. As an ex Forest player I will not let one scumbag ruin my respect for the Forest fans.
"Incredibly proud to be captain of this group of Sheffield United players, they gave their all and can hold their heads up high. We will be back and go again. Thanks for all your messages and support after the incident."