Arsenal could be without Santi Cazorla for the rest of the season after the Spain international suffered a reaction in his Achilles while undergoing rehabilitation from knee-ligament surgery.
Cazorla has not featured for Arsenal since rupturing his lateral collateral ligament during the 1-1 draw at Norwich City on November 29.
Manager Arsene Wenger had been hopeful the playmaker would return for the second-leg the Champions League last-16 tie at Barcelona later this month but he is no longer so optimistic and feels an April comeback might be out of reach.
"Santi is not doing too well," Wenger 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 [training].
"It has been a reaction to coming back. A return in April? We have to see now how he responds.
"He always had a little tendinitis in his Achilles and we have to see how he responds to that."
Wenger confirmed Alex Oxlade-Chamberlain would be out for six to eight weeks with the knee ligament injury he sustained in the 2-0 defeat to Barcelona at the Emirates Stadium but added the England midfielder would not require surgery.
"We feared surgery at some stage before we saw the MRI. In the end we got, on that front, positive news," he said.
The Euro 2016 prospects of another Englishman, Jack Wilshere appear to be increasingly remote.
Wilshere suffered a fractured fibula on the eve of this season and is yet to feature having undergone an operation in September.
He is still a month away from playing, meaning he will not be in contention for England's forthcoming friendlies against Germany and Netherlands
"Jack is doing quite well but has still not been outside yet, running," Wenger added. "He starts again, I think, this week. He will be three to four weeks [more] out."