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.