Arsenal boss Mikel Arteta has delivered an update on Takehiro Tomiyasu and William Saliba's injuries.
Both were injured against Sporting Lisbon and missed Sunday's match against Crystal Palace.
"The doctor is assessing [Tomiyasu]. We have one assessment and I think they need to have another assessment tomorrow. It's not looking good," Arteta said in a press conference after the 4-1 win.
"Tomi is not one to exaggerate things. He was really concerned straight away and we are concerned.
"We hope Willy [Saliba] is going to be better news. Again we have to wait to tomorrow to get a better picture."