William Saliba has quickly established himself as one of Arsenal’s most important players since he joined the squad last season. Arsenal were on their way to an unexpected Premier League title, but saw their form collapse when Saliba picked up a season-ending injury, and Rob Holding could not replicate his influence in the back line. The 22-year-old is already one of the best defenders in the Premier League, with his composure and ability on the ball coupled with incredible physical strength. Holding, who left in the summer after failing to provide inadequate cover for Saliba, has now made a s…