Referee Yuichi Nishimura could be in trouble after he was accused of using insulting language toward a player during a J. League match on Tuesday between FC Tokyo and Oita Trinita, it was learned Wednesday.

Nishimura allegedly told Oita defender Taikai Uemoto to "die" after he remonstrated over one of his decisions late in Oita's 1-0 defeat at Ajinomoto Stadium.

Oita team official Yasushi Hara said he will collect evidence from the player over the incident and plans to send a letter of protest to the Japan Football Association's disciplinary committee.

"I was shocked," Uemoto was quoted by local media as saying. "If one of us players had said the same thing (to the ref) we would have been sent off."