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.
"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."
"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."
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.
