Arsenal manager Mikel Arteta says Bukayo Saka and Martin Odegaard both face late fitness tests ahead of Wednesday's game against Bayern Munich.
The Gunners travel to the Allianz Arena having drawn 2-2 in the first leg of their quarter-final against the German side.
Arsenal's hopes of winning the Premier League title took a huge blow on Sunday as they were beaten 2-0 at home by Aston Villa.
To make matters worse, Saka and Odegaard both suffered injuries in the game, and could now miss the vital second leg against Munich.
Speaking at the press conference ahead of Wednesday's game, Arteta said: "Obviously we had only less than 48 hours to recover for the game and we've done very little training.
"So we'll assess them tomorrow and see how they are."
If Arsenal are able to get past Munich they will reach the semi-finals of the Champions League for the first time in 15 years.
"That would be unbelievable," added Arteta.
"If we make semi-final, we would be in a high emotional state, there is an opportunity.
"Depending on their approach, I want our team to be ourselves. Sometimes your opponent doesn't allow you, but we are looking at the best way to win the game."
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