A fan appeared to kick and punch Sunderland defender Luke O'Nien during Thursday's ill-tempered League One play-off clash, with the player saying he was asked by police if he wanted to press charges.
O'Nien went tumbling over the advertising hoardings and into the stand following a challenge with Tom Naylor in the second-half at Fratton Park.
TV footage showed a fan aim a kick and a punch at the Sunderland player after he fell into the front row of home fans.
Sunderland midfielder Lee Cattermole clearly saw the fracas and exchanged words with fans as he helped his team-mate back on the pitch.