Championship Doncaster are investigating the possibility of taking legal action after a challenge by Bristol City's Yannick Bolasie left Rovers winger James Coppinger with a broken cheekbone. The challenge went unpunished by referee Fred Graham but the severity of Coppinger's injury means he is expected to miss the rest of the season.
Chairman John Ryan told Doncaster's official website: "I was disappointed that the referee did not take any action against the lad for the late challenge, but I have taken legal advice regarding this matter."
Speaking about the incident on BBC Radio Sheffield, Rovers boss Dean Saunders said: "He's fractured his cheekbone and it's an absolutely outrageous head butt.
"It's right in front of me and the referee's not even spoken to the lad."