Arsenal forwards, Bukayo Saka and Gabriel Martinelli, were missing from training on Monday.
The Gunners are preparing to face PSV Eindhoven in their final Champions League group fixture on Tuesday night.
Mikel Arteta is likely to be without his first-choice widemen for the game in the Netherlands.
Martinelli missed training due to illness while Saka has suffered a knock to his foot.
Both players are unlikely to make the trip to Eindhoven later in the day.
Emile Smith Rowe is, however, back training with the group.
A decision on whether he travels is to be taken post-session.
UCL: Saka, Martinelli missing from Arsenal training ahead of PSV squad