Arsenal manager Arsene Wenger admits Mathieu Debuchy is "destroyed" and "embarrassed" after it was confirmed the injured defender would endure a second lengthy spell on the sidelines this season.
Debuchy has started only nine Barclays Premier League games since joining the Gunners from Newcastle in the summer.
The France full-back was out for three months earlier in the season following ankle ligament surgery in September and will now miss another three months after an operation on his right shoulder.
"He is destroyed," Wenger said. "He is such a keen player, so professional and so willing.
"It is his first year here and of course he is embarrassed. But it is not his fault."
Arsenal's injury list
Arsenal's injury list
1/5 Mikel Arteta (midfield)
Like Diaby, the Spaniard is closing in on a return but the Swansea match will come to soon. The club captain last played in November.
2/5 Mathieu Debuchy (defender)
Returned in the FA Cup semi-final win over Reading but has since been ruled out with injury and Wenger confirmed he remains 'unavailable'.
3/5 Alex Oxlade-Chamberlain (midfield)
Suffered a hamstring injury against Manchester United in the FA Cup and hasn't played since as it has exacerbated a groin problem. Out at least until May and facing surgery in the summer.
4/5 Aaron Ramsey (midfield)
Aaron Ramsey caught a kick on his calf during the win over Hull and was later substituted. The Welshman was rated 50/50 for the Swansea match by Wenger, but it now appears that he is a major doubt for the clash at the Emirates.
5/5 Danny Welbeck (forward)
Danny Welbeck has not played since the goalless draw with Chelsea towards the end of April after suffering a knee injury. Wenger has confirmed that the injury is 'nothing major', and that he should return to full fitness before the end of the season.
Debuchy had to be carried off on a stretcher in the 13th minute of Arsenal's 3-0 win over Stoke last Sunday after he was pushed into the advertising hoardings by Potters midfielder Marko Arnautovic.
"The push was not needed," Wenger continued.
"It was a bit unlucky as well because there was a divot after the touchline which may have made it worse.
"Arnautovic did not have a chance to get the ball - I don't think it was malicious but he had no chance to get the ball so I'm saying it was not needed.
"It's not obvious what his intention was, I don't think he wanted to hurt him but I don't think it was needed."
Arsenal visit Manchester City on Sunday, hoping to avenge last season's 6-3 hammering at the Etihad Stadium.
One player who could make the difference for the Gunners this term is Alexis Sanchez, whom City boss Manuel Pellegrini described this week as "the best player in England".
"It's a great compliment because Pellegrini knows football well," Wenger said.
"I agree with him - at the moment Sanchez is one of the top performers in the league."
Sanchez has 18 goals in all competitions this season, one fewer than City striker Sergio Aguero.
Aguero could make his first start since December 3 against Arsenal on Sunday, after the Argentine recovered from a knee injury.
"There are some other great players but Sanchez and Aguero are two of the best performing since the start of the season," Wenger said.
"Aguero has been less consistent because he's been injured more - in the last year he has suffered from being a bit in and out - but of course he is a world-class player.
"Alexis is full of energy, full of enthusiasm as well. That is what is fantastically refreshing when you see the number of games he's had to play - he's always keen to go out and play.
"What everyone admires about him is his game is always full of enthusiasm, a desire to do well, to take people on and fight to get the ball back. It's fantastic and it's infectious."
Kieran Gibbs will have a fitness test on Friday but is expected to have overcome a heel problem while Mesut Ozil, Calum Chambers and Theo Walcott are all fit again.
Wenger had hoped Danny Welbeck would also be available for the trip to Manchester but his thigh injury has not healed as fast as expected.
"That was the wrong hope," Wenger said. "I think he has two more weeks."