Getting loads of questions about not having a reserve team.
Now its all because of the Professional Development League that was established
The U21 age-range was set up for the first time with the introduction of the Professional Development League.
Teams are allowed to field three overage outfield players and one overage goalkeeper.
This is a great article that explains the whole thing much better than I can
http://en.wikipedia.org/wiki/2013%E2%80%9314_Professional_U21_Development_League