Chelsea and their Champions League rivals have all named their squads for the Champions League's league phase, and clubs have been forced to make some tough decisions
Player List A
Goalkeepers
Robert Sanchez
Filip Jorgensen
Defenders
Tosin Adarabioyo
Benoit Badiashile
Trevoh Chalobah
Levi Colwill
Marc Cucurella
Wesley Fofana
Malo Gusto
Jorell Hato
Reece James
Midfielders
Moises Caicedo
Dario Essugo
Enzo Fernandez
Andrey Santos
Forwards
Liam Delap
Alejandro Garnacho
Jamie Gittens
Marc Guiu
Pedro Neto
Cole Palmer
Joao Pedro
Estevao Willian
Player list B
Josh Acheampong
Tyrique George
Romeo Lavia
Clubs are entitled to register an unlimited number of players on List B during the season if they are born on or after 1 January 2003 and are eligible*.
Chelsea have left a number of stars out of their squad for the Champions League. High earner Raheem Sterling is among those to miss the cut, while deadline day signing Facundo Buonanotte is another notable absentee.
Enzo Maresca's Blues qualified for the Champions League after finishing fourth in the Premier League last season. They have since made a number of significant additions to their ranks, with Brazilian wonderkid Estevao and former Manchester United winger Alejandro Garnacho arriving in a £300m summer.
Teams are required to provide an A List for the competition, and are allowed to update their squads in the new year to bring in January signings. They are also allowed an unlimited number ot B List players, who must have been born after January 1, 2004 and meet eligibility criteria.
According to UEFA's rules, as relaid on Chelsea's website: "To be eligible for a player List B, the squad member must be born on or after 1 January 2004 and has, since his 15th birthday, been eligible to play for the club concerned for any uninterrupted period of two years, or a total of three consecutive years with a maximum of one loan period to a club from the same association for a period not longer than one year".
Romeo Lavia qualifies for the B List under those criteria, as do Chelsea academy graduates including Josh Acheampong and Tyrique George. Buonanotte, however, would have needed to be named on the main list after joining from Brighton on loan.
"It’s a great opportunity for me and I’m just looking to add as much to the squad as possible, help the team and help the staff," Buonanotte said after joining Chelsea on deadline day. However, he will be restricted to appearances in domestic competitions.
Teams are permitted to name up to 25 players in their squad if that tally includes four club-trained players. The Blues have only included three - Reece James, Trevoh Chalobah and injured defender Levi Colwill - so their A List contingent is made up of just 24.
Chelsea will kick off their Champions League campaign away to Bayern Munich, with Barcelona and Napoli among their other league phase opponents. Nicolas Jackson has been named in Bayern's squad after joining on loan from Chelsea and will be available to face his parent club.
Maresca's team aren't the only ones who have left a summer signing out of their European squad. Mathys Tel, who joined Tottenham permanently after a spell on loan from Bayern Munich, hasn't made the cut.
Elsewhere, Arsenal have left Gabriel Jesus out of their selection as they wait for the Brazilian to recover from an ACL injury. Spurs have also left out some injured stars, with ACL victim James Maddison and Sweden international Dejan Kulusevski among those absent.