What happened: William Saliba has traveled with Arsenal for the club's Champions League fixture against Slavia. The 25-year-old defender returned to full training this week after missing more than 100 days of action.

Why it matters: He had been sidelined since the summer after sustaining a lower back injury at the World Cup, where Saliba played through back pain before undergoing surgery. His return strengthens an Arsenal side currently sitting clear at the top of the Premier League table.

What to watch: Arsenal face Slavia in European competition before resuming their domestic league campaign.