Hector Bellerin and Kieran Tierney both suffered injuries at Monday's game against West Ham.
The Spain international was named in the starting line-up but had to step down after picking up a knock during the warm-up. Ainsley Maitland-Niles took his place.
And Tierney was forced off in the second half after falling badly during a West Ham attack.
"Tierney, I think it's something with his shoulder but I don't know exactly what it is," said Freddie Ljungberg. "But obviously we had to take him off so I think he's going to maybe go to hospital and check what it is.
"Hector had a bit of feeling, I think, in his hamstring in the warm up. Then we took the decision. I said I'm not going to force anyone to play if you don't feel 100 per cent.
"So we took him off and had a straight swap on that with Ainsley, and Ainsley had been out in the cold for a little bit and comes on and does really well, so I'm really proud of him and happy for him."
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