Arsenal manager Arsene Wenger has confirmed Aaron Ramsey will be sidelined by a hamstring injury, while revealing Alexis Sanchez has reached the point of exhaustion.
The Gunners recorded an important 2-0 win over Bayern Munich on Tuesday to keep their Champions League hopes alive, having lost their opening two matches in Group F.
The victory came at a cost for Wenger though, with Ramsey having to be replaced by Alex Oxlade-Chamberlain after 57 minutes.
"He is very down," the Frenchman said of his Welsh midfielder after the match.
"He told me that the hamstring is a tough one. He is out, yes."
Ramsey himself was thrilled to see Arsenal pick up three points but admitted the injury is a major blow at such a vital time in their European campaign.
"Fantastic result for us, we worked so hard for it," he wrote on Twitter. "Gutted to have to come off but was buzzing watching the lads at the end."
The Wales international suffered three hamstring injuries throughout the course of last season. It is not known yet how long he will be out of action for.
According to Wenger, star forward Sanchez is in need of an urgent rest.
The Chile international was almost rested prior to scoring twice in Arsenal's 3-0 win over Watford on Saturday and played another 82 minutes against Bayern.
"You could see he was a bit jaded physically," Wenger said.
"He pushes himself so much but he finished exhausted. He played two games with Chile, plus the travelling, plus Watford, plus this game - it is too much."
Arsenal's next match is at home to Everton in the Premier League on Saturday.
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