Liverpool has confirmed the extent of Conor Bradley's injury, with the club revealing the right-back has suffered a "significant" knee problem.
Bradley went down during the latter stages of Thursday's goalless draw with Arsenal in north London. The Northern Ireland international looked to be a lot of pain as he tried to clear the ball, before he was pushed by Gabriel Martinelli as he lay writhing on the ground.
The 22-year-old had to be stretchered off the pitch and was seen leaving the Emirates Stadium on crutches, with Liverpool now confirming that he will have to undergo surgery, with his season now over.
In a statement, the club said: "Liverpool FC can confirm Conor Bradley has sustained a significant knee injury."
It added: "Bradley will undergo surgery in the coming days and then begin a period of rehabilitation at the AXA Training Centre.
"No timeframe is being placed on his return to playing at this stage of the process."
Liverpool.com understands that while Bradley's injury is not an ACL, as was speculated in the immediate aftermath of Thursday's game, the problem does involve damage to bone and ligament.
While the club has not offered a timeframe, Bradley is understood to be out for the rest of the domestic season. It remains to be whether he will be able to recover in time should Northern Ireland reach this summer's World Cup.
Michael O'Neill's side faces Italy in a play-off at the end of March, with the winner of that game going on to face one of Wales or Bosnia and Herzegovina for a place at the tournament, although Bradley will of course now miss both games.
The news comes as another blow for Liverpool boss Arne Slot, for whom the injury list is beginning to pile up.
Giovanni Leoni is also expected to miss the rest of the season, while Alexander Isak is out for a lengthy spell after breaking his leg against Tottenham.
There are also doubts over Hugo Ekitike's fitness after he picked up a hamstring problem, although Slot has suggested he could return against Barnsley in the FA Cup on Monday.