He also played at Brighton in our opening match of the 2020/21 campaign, before heading down the road to Fulham for a loan spell. His time at the Cottage proved productive as he racked up over 2000 minutes of football, including 30 Premier League appearances.
‘I thought it was the most important for me at that time,’ he says.
‘I came back from injury but didn’t feel myself, didn’t feel powerful, wasn’t running past people and felt like I lost a lot of muscle and power. So for me, mentally, I just wanted to go somewhere where I could play a lot and get that feel and confidence back after such a long time out with such a bad injury.
‘I felt like I had to get away and play as much football as possible, and I got that.’
Now Ruben’s focus is on reaching top form in a Chelsea shirt again. For Callum, it is making the most of a first proper pre-season in three years to ensure he hits the ground running when the competitive action begins in Belfast on 11 August.