Sporting Lisbon have condemned reported acts of violence towards some of their players by a group of fans at the club's training ground on Tuesday.
The Portuguese Primeira Liga club finished the season third after a 2-1 defeat at Maritimo on Sunday and just missed out on a place in next season's Champions League.
The players were preparing for Sunday's Portuguese Cup final, where they take on Alves, when the alleged attacks took place.
A statement on the club's official website read: "Sporting Clube de Portugal vehemently condemned the events registered today at the Sporting Academy.
"We can not in any way agree with acts of vandalism and aggression to athletes, coaches and staff of professional football, nor with attitudes that configure the practice of crime that in no way honour and ennoble Sporting Clube de Portugal.
"Sporting is not this, Sporting can not be this.
O Sporting Clube de Portugal repudia de forma veemente os acontecimentos registados hoje na Academia Sporting.May 15, 2018
"We will make every effort to establish full responsibility for what has happened and we will not fail to demand the punishment of those who acted in this absolutely pitiful way."