Arsenal's Oleksandr Zinchenko has reportedly failed to recover from a calf injury in time and is a doubt for their clash with Crystal Palace at the weekend.
Mikel Arteta's side have been in Dubai this week for some warm-weather training during the Premier League's brief winter break.
Arsenal were last in action against Liverpool in the FA Cup third round on January 7, but return to face Palace in the lunchtime kickoff on Saturday.
Zinchenko was absent from the side that lost 2-0 to Jurgen Klopp's men at the Emirates Stadium, after also missing their 2-1 defeat at Fulham on New Year's Eve.
The Evening Standard claims that the Ukrainian is doubtful for Saturday's encounter, having not yet fully recovered following their training camp in the Middle East.
Zinchenko has been the regular choice at left-back so far this season, making 24 appearances in all competitions.
An opening-day injury to new signing Jurrien Timber is believed to have ended his campaign, as he was set to be the starting left-back this season.
In the absence of those two, Jakub Kiwior has been thrust into the side out-of-position, given that Takehiro Tomiyasu is away on international duty at the Asian Cup with Japan.
Kiwior was the unfortunate man who put through his own net to give Liverpool the lead in their FA Cup tie just over a week ago, but the Poland international is set to start again given the lack of options available to Arteta.
Cedric Soares was the only senior defender on the bench for the clash with Liverpool, as Arsenal are down to the barebones at the back.
Despite misfiring in attack over the past few weeks, the fact that Arsenal have kept just one clean sheet in their last nine games is a big factor in their recent drop in form.
Arteta's side have won just one of their last seven games, and go into the Palace fixture on the back of three successive defeats.
That saw their FA Cup hopes dashed, as well as falling five points adrift of leaders Liverpool, despite topping the table on Christmas Day.