​Harwood-Bellis (left) joined Villa from Southampton on transfer deadline day [Getty Images]Aston Villa have left new signing Taylor Harwood-Bellis and teenage striker Brian Madjo out of their squad for the league stage of the Champions League in what manager Unai Emery described as a “hard” decision.Central defender Harwood-Bellis joined the Midlands club for an initial £25m from Southampton on transfer deadline day, while 17-year-old Madjo impressed when he scored Villa’s equaliser against Paris St-Germain in a 2-1 Super Cup defeat in August.That has been Madjo’s only appearance this season with Emery, whose side have lost both their opening Premier League games to Brighton and Arsenal, saying the forward is injured.”It’s hard for the decision we took and for the players too,” said Emery prior to his side’s top-flight game at Hull on Saturday (17:30 BST).”But the experience we have here with some players before as well, two years ago, [Donyell] Malen and Andres [Garcia] were out.”Of course, to decide it is through our analysis of how we expect to be until January in the Champions League. We are going to play eight matches.”[Modou Keba] Cisse is not in because he is injured. Madjo is injured, hopefully not for so many weeks but still injured for the next two weeks minimum. And they are both out.”Taylor arrived as the last one and we can get the balance with Lamare Bogarde in case we need a centre-back or we even can play [Boubacar] Kamara.”We decided trying to analyse everything deeply. But of course, Taylor signed here for a long time. He stays here for a long time, and hopefully they will have again an opportunity to play in Europe with us. Hopefully after January, maybe, or the next years.”Madjo is 17 years old, still being so, so young, and of course he will have more opportunities to play with us this year or the next year in Europe.”Villa open their Champions League campaign against Club Brugge on Tuesday, 8 September.How do European squad lists work?Aston Villa sign Mbaye and Harwood-Bellis