Each competing club has to submit a List A of their playing staff which comprises up to 25 players with a minimum of eight locally trained players, of whom four must have come through the club’s own ranks between the ages of 15 and 21.
Any shortfall in those eight reduces the overall number available, and UEFA have announced five substitutions will be permitted this season, increasing the number of players selected for a matchday squad to 23.
In addition there is List B, made up of players aged 21 or younger with two years’ training at the club. This list can be updated at any time up to midnight before a Champions League match. In Chelsea’s List A submitted for the 2020/21 group stage, Andreas Christensen, Tammy Abraham, Fikayo Tomori and Ben Chilwell are locally trained players, with the first three classed as club-trained and Chilwell association-trained.
Mason Mount, Callum Hudson-Odoi, Reece James and Billy Gilmour qualify to be submitted on List B.