Santi Cazorla faces missing the rest of the season after Arsene Wenger revealed the Arsenal midfielder has suffered an Achilles problem.
The Spain international has been out since November with a knee injury but now has an issue with tendonitis which could yet rule him out for the remainder of the campaign.
The Gunners have struggled with Cazorla on the sidelines and are five points off the top of the Barclays Premier League table after Sunday's defeat at Manchester United.
It was initially hoped the 31-year-old would be back at some point in March but - ahead of Wednesday night's game with Swansea - Wenger gave a fresh prognosis on Cazorla.
"Santi is not doing too well," he said.
"He has some Achilles problems that hold him back. His knee is doing well but his Achilles has inflamed a little bit and we have to put him off impact.
Asked if he is now set to return in April, Wenger replied: "We have to see now how he responds. He had always a little tendonitis on his Achilles and we have to see how he responds to that."
Fellow midfielder Jack Wilshere is still looking at a minimum of three weeks before making his own long-awaited return having not played this season due to a broken fibula.
He is now set to miss England's friendly double-header later this month with Wenger confirming he has not started training with the squad as of yet.
"Jack is doing quite well but has still not been outside yet," he said.
"Running, I think, starts again this week. Three to four weeks (until he is back). I can understand you worry for the England team. I worry as well. I'm a supporter of England."
With experienced campaigners Mikel Arteta and Tomas Rosicky also out, Wenger's options in the middle of the park are limited.
The Frenchman has come in for criticism in recent days after the Old Trafford defeat saw Arsenal suffer a set-back in the race for their first league title in 12 years.
But the 66-year-old insists he has become immune to those who have derided both him and his team having been in the job for two decades.
"We live in a society where the excess is permanent but when the excess is permanent it becomes ineffective," he said.
"You become immune to it. In life you have to focus on what can influence your life. People are entitled to their opinion but what can influence my life and the life of the club is putting a good performance on.
"Football is a pleasure. We should not forget that. Football is fantastic as well because it's unpredictable and not mathematical. We have to accept that it's like that and that it is fantastic like that."
Leicester top the table while Arsenal's fierce local rivals Tottenham are second ahead of the north London derby at the weekend.
Wenger said his side will scrap for the championship but will happily shake hands with the winners come May.
"Let's fight with them," he added.
"I've fought for that idea for years, that football is unpredictable and teams like Leicester can come in to the top four.
"At the end of the day let's fight with them. If on the last day of the season they are in front of us we congratulate them and say well done.
"They can also be behind us so let's fight, and hope they are behind us.
"Life is not black and white. Life is nuanced. What you want is to get the best out of the team until the end of the season and feel that this team gave absolutely the best in every game until the end of the season. After that, you want to win but we will see who will win."