Arsenal boss Mikel Arteta admits left-back is wide open ahead of facing Europa League semifinal opponents Villarreal.

Arteta confirmed that he would assess Kieran Tierney's fitness in Wednesday's training session, as he continues his rehabilitation from a knee injury.

But Granit Xhaka has proved a capable deputy, and Arteta says the lack of rotation in that area since Tierney's injury was designed to help the midfielder learn the role.

"It's been one of the reasons, because of the way we wanted to play and the players around. We have managed to get some clean sheets since he's been playing there and that's something that didn't happen for 13 games. He gives something different to the team."

Another option is Cedric Soares.

"He's been a bit unfortunate because he played some good games as a right back as well," Arteta said. "Ten we had the injury of Kieran and he played some as a left back and we were training with him as a left-back.

“We could have given him more opportunities, but it's true that Calum came in and did really well. We are training this afternoon so we will see how everybody is."