Aston Villa begin their Champions League campaign on Tuesday and it will be without a key figure in Douglas Luiz. The Brazil international played a huge part in Aston Villa reaching the elite competition, not just last season, but ever since he joined the club in 2019 and how he helped the Midlands outfit rise again. But Villa had to sell Luiz to Juventus in the summer for Profit and Sustainability Rules (PSR) and many felt that a big void had been left in the club’s midfield. Unai Emery would only get a true answer once the new season began, and four Premier League games in, the sense is that…