Kieran Gibbs and Johan Djourou are major doubts for Arsenal's game with Liverpool on Saturday after picking up knocks.
Both men hobbled out of the Gunners' 1-0 victory over Udinese in the UEFA Champions League play-offs on Tuesday.
Gibbs lasted 45 minutes at Emirates Stadium, but was forced to make way at the interval.
It was quickly announced that he had suffered a hamstring strain and was in no position to continue.
The England international has struggled with injuries over recent times and will be disappointed to find himself back on the treatment table - especially as the sale of Gael Clichy has opened the door to a regular role at left-back.
He was replaced in midweek by Djourou, but he lasted less than 10 minutes before being forced from the field himself.
The Swiss defender also suffered a hamstring injury and looked to be in some pain as he trudged from the field.
The setbacks for Djourou and Gibbs have presented Arsene Wenger with an unwelcome selection dilemma ahead of a crucial Premier League clash with Liverpool this weekend.
It is hoped that the pair will return to action in the near future, but both are highly unlikely to figure against Kenny Dalglish's Reds.
A statement on Arsenal's official website read: "Kieran Gibbs and Johan Djourou both picked up minor hamstring problems during Arsenal's 1-0 win over Udinese on Tuesday night.
"Gibbs was replaced by Djourou at half time and the Swiss defender was in turn replaced by Carl Jenkinson 10 minutes later.
"Both players could miss Saturday's game against Liverpool."