Arsenal defender Kieran Tierney is due to undergo surgery this week on a knee injury that is expected to rule him out for the rest of the season.
Tierney has been struggling with the issue for a number of weeks but had previously been able to continue playing through it.
After returning from international duty and feeling discomfort in training last Thursday, the left-back underwent a scan and that revealed the extent of the damage.
Tierney duly missed Monday night’s trip to Crystal Palace and he went to see a specialist on Tuesday.
It was decided the best course of action was for the Scotland international to have surgery and he is expected to miss the rest of the season.
Arsenal and Tierney will not know how long he will spend on the sidelines until surgery has been completed and the club can begin to monitor his recovery.
Tierney’s absence is a big blow to Arsenal, who slumped to a 3-0 defeat at Crystal Palace on Monday night without him.
Nuno Tavares filled in at left-back, but the youngster was taken off at half-time by Mikel Arteta and Granit Xhaka moved into defence.
Arsenal’s injury woes were made worse by Thomas Partey limping off on Monday night and he is a doubt for Saturday’s game against Brighton due to a thigh issue.
“It’s what we have, it’s the numbers that we have,” said Arteta. “We’ve lost Kieran and we’ve lost Thomas now and that’s it.
“With the players that we have we will keep trying like we have since the start of the season, but we never had a big squad so we can’t find any excuses.
“Today we have to look at ourselves and I’m the first one because, I repeat myself, it wasn’t good enough.”
