Nacho Monreal was taken off during the first half of our 3-1 win over Burnley on Saturday, forcing Unai Emery into another defensive reshuffle.
However, after the game Emery said he was optimistic the problem wouldn’t be serious.
“It’s starting to be a muscular problem and we decided to change and not take more risks with him. But I hope it’s not big and I hope he can be with us next week.
“I don’t know if he can play at Brighton, but we can play, I think, Koscielny.
“Also Mustafi is close to coming with us. We can take more injuries but we can also recover more players.”
Two goals from Pierre-Emerick Aubameyang and one from Alex Iwobi gave Arsenal a 3-1 win over Burnley on Saturday.
Auba opened the scoring when finishing a brilliant team move early on, before the striker scored his 12th Premier League goal of the season shortly after the break.
Ashley Barnes pulled one back but Iwobi came off the bench to make the points safe for Arsenal later on.