A man arrested on suspicion of headbutting Roy Keane has been released on bail until late September.The 42-year-old is accused of assault causing actual bodily harm over a confrontation with Keane at the Emirates Stadium on Sunday.Footage was posted on social media of fellow Sky Sports pundit Micah Richards stepping in to move the suspect away from Keane.The confrontation followed Arsenal's 3-1 victory over Manchester United.The Metropolitan Police refused to name anyone involved in the incident, but released a statement that said: "Police are investigating an incident at Emirates Stadium on Sunday, 3 September, during which a man was assaulted."On Monday, 4 September, a 42-year-old man was arrested on suspicion of assault (ABH)."The man was taken into police custody before being released on bail until a date in late September."Inquiries are ongoing."