這個問題可能適用於其他地方的其他聯賽，但是最近我看到了一篇有關Radamel Falcao playing for the Manchester United U-21 team和Rafael doing the same thing的文章。兩位球員都超過21歲，並為曼聯高齡球隊進行半常規起步。顯然年齡過大的U-21預備隊也該如何參加比賽？
Because the rules say that they can:
Clubs are only allowed to field three outfield players over the age of 21, plus the goalkeeper is also permitted to be over 21.
The rules allow for up to three overage outfield players as well as the goalkeeper to be over the age of 21. Usually these players are struggling players whom the manager wants to get playing time or they are players coming back from injury and the manager wants to know if they are game ready.