It has been a long road back for Hector Bellerin and Kieran Tierney, but they are closing in on making a consistent returns to the first team.
Both have featured in recent weeks, so could they continue their progress against Standard Liege on Thursday night?
"Tierney still needs time and confidence, training and playing," Unai Emery said. "Thursday is a good opportunity again, because he is ready to play. He will take minutes, he will take confidence and will be able with us to show also his progress.
"He didn't play in Manchester because he had a small problem - not important - but the doctor told us that it's better for him to be here, working alone and preparing for the match tomorrow.