Millwall goalkeeper could face further punishment for his horror challenge on Jean-Philippe Mateta.
Crystal Palace striker Mateta was taken to hospital after being kicked in the head by Roberts in the eighth minute of Palace's 3-1 FA Cup fifth-round win on Saturday.
Roberts was sent off after a VAR review, with the footage showing he kicked the side of Mateta's head, having dashed from his line to clear the ball. Play was initially allowed to carry on by referee Michael Oliver.
The 27-year-old forward was treated on the pitch and given oxygen before being taken to an ambulance.