Crystal Palace manager Roy Hodgson admitted Eberechi Eze showed 'naivety' when he became the latest footballer to breach coronavirus protocols last weekend.
The playmaker attended former club QPR's FA Cup tie with Fulham on Saturday and failed to wear a mask at all times while at Loftus Road.
Eze, 22, was also not socially distanced, with just a seat between him and another person in the directors' box.
A statement from Palace on Monday insisted they would deal with the matter internally and described his actions as an 'error of judgement'.