Derby County captain Richard Keogh could be ruled out until December 2020.
Sky Sports report that the former Bristol City defender will be out of action for up to 15 months after damaging two knee ligaments in a controversial incident last week.
The 33-year-old, who spent three years at the Robins between 2005 and 2008, injured his knee in a car crash last week that saw young teammates Mason Bennett and Tom Lawrence arrested for drink driving.
Derby issued a damning statement over the incident, in which only Keogh was referred to by name.
The injury has already ruled him out of Euro 2020 should Ireland qualify for the tournament, and it will now have an impact on his involvement next season.
Derby boss Philip Cocu admitted last week that Keogh felt responsible for the incident, which happened after a team bonding exercise.
He said: "The first idea was footgolf but the weather was really bad so we changed plans and went bowling.
"After that, there was a team dinner where the team sat together for some bonding. Most of the players left around 8pm and a small group stayed and continued at the bar.
"Due to an alcohol-related incident we've lost our captain for the rest of the season, so in the end it was bad news for the whole team.
"It's bad news and a bad situation for everybody at the club."
He added: "I've spoken to him. He was here [at the training ground] for a short moment and I spoke briefly to him because there's a lot going on.
"He's extremely down, of course, because he realises what's going on for him personally and of course as a responsible player, as captain, to not be part of the team any more does something to you.
"I think he feels responsible, yeah.
"The more senior players always have to step up and take responsibility and it's now had a huge effect on him personally. It's a lot to deal with for him."
