Derby County captain Richard Keogh could be out for up to 15 months after sustaining knee ligament damage on the night of a crash that led to the arrest of two of his team-mates.
Tom Lawrence and Mason Bennett were charged with drink-driving following the incident in Derby’s Allestree area on Tuesday, 24 September.
Derby said that Keogh, 33, had been hurt in an “alcohol-related incident”.
The defender was initially ruled out for the rest of the season.
However, the Republic of Ireland centre-back may now be out until December 2020.
The crash followed a team-building dinner, and Derby have said there will be a “rigorous internal investigation”.
A statement added that those involved “know they will pay a heavy price for their actions” but also said they would be supported with their “rehabilitation back into the squad and team”.
Lawrence and Bennett were both left out of the squad for Saturday’s 3-2 win over Birmingham City, their first home victory of the season.