Tierney was absent from the matchday squad on Thursday as Arsenal and Crystal Palace played out a dire 0-0 draw at the Emirates.
The left-back was forced to pull out of the game just hours before kick-off, meaning Arteta’s tactical approach had to be switched up at short notice.
Arsenal are in the dark over the severity of Tierney’s injury but Arteta suggested that fatigue was a factor.
He told Sky Sports: “Tierney had some muscle soreness, he didn’t recover well and wasn’t comfortable to start the game and in this period we can’t take the risk.”
He added: “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;
“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 [on 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.”
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