Wigan are looking into an incident in which England goalkeeper Chris Kirkland was apparently struck by a coin during his side's dramatic 1-0 victory over Burnley.
The match at the DW Stadium was halted by referee Mike Jones in the 53rd minute for Kirkland to receive treatment.
Kirkland was not allowed to comment on the incident, but Wigan boss Roberto Martinez said: "We're trying to find out (what happened). We think it was a coin. We're not too sure about it, but it's one of those events you don't want to see on a football pitch."
Kirkland, with his back towards the Burnley fans amassed behind his goal in the second half, was seen rubbing the top of his head.
Wearing a pained and quizzical expression, Kirkland's gaze was directed to the Clarets supporters as he attempted to seek out the perpetrator.
Crucially for Wigan, Kirkland was uninjured and able to continue, producing a vital save in the dying stages moments prior to Hugo Rodallega heading home a last-gasp winner.
He added: "I was relieved and pleased Chris carried on in the game because can you imagine if he'd been carried off because someone threw a coin. He then produced a key moment in the game when he saved late on from (David) Nugent."
Asked whether he harboured any concerns over a potential Football Association inquiry, Martinez added: "You cannot take coins from the away fans.
"What occurred is something the authorities need to look into, and something we don't want to see on a football pitch. It shouldn't be in modern football.
"It's different if you allow someone to bring in a big stick, a flag or something that is not allowed."