He was injured after 53 minutes in the match Wigan won with the only goal in the last seconds of injury-time.
Foul play: Kirkland winces in pain after the coin strikes
Referee Mike Jones stopped the match and will send a report to the FA, who will launch an inquiry. As Kirkland was receiving treatment the referee spoke to the chief steward.
Police and stewards moved in to face the Burnley fans behind the goal. Both clubs could be punished.
Wigan, because the offence took place on their ground and Burnley because the coin clearly came from the end of the ground where alltheir fans were housed.
Kirkland resumed after the injury which, according to manager Roberto Martinez, leftmarks on his forehead and on the back of his head.
Kirkland said he was told not to speak about the incident but his manager added: 'I was just relieved thatChris could carry on in the game. In the last minute he made a great save.
'It is something the authorities need to look into. Maybe it would be a great way to help the finances of the club if we check away fans' pockets before they come in,' he smiled.
Burnley manager Brian Laws said: 'I'm going to do an Arsene Wenger here, in that I didn't see it. I would rather talk about the performance of my team.'