Kieran Tierney muscular injury is not serious and he is targeting the Newcastle match on Monday as a return date, football.london understands.
The 23-year-old has been one of Arsenal's most impressive players this season and was part of a defence which kept three clean sheets in a row.
Tierney has scored one goal and made three assists in his last three league games and football.london has been told that his'slight calf strain' injury is 'not serious'
"He's a real threat and the way we attack on the left is really important, but he wasn't here and we need to find other solutions," said Arteta after the draw with Palace.
"It is a challenge when you have created a game plan for the day and a few hours before the game he has to pull out.
"Kieran's progression in the last few months has been incredible and now it is time for another player to step in. He's going to have an MRI scan tomorrow and see how he is.
'We don't know (how long he will be out for), we will probably know more tomorrow [Friday] after testing him and how long he is going to be out for. It was a big disappointment to lose him and hopefully he will be back with us shortly."
Arsenal face Newcastle in the Premier League on Monday night just a week after playing them in the FA Cup third round.
