if you had 14 player`s at end of season and 1 of them was retiring then Nordeus will replace player of similar age so you have 14 man squad for new season
edit; you could have say 16 man squad and if 3 player`s were to retire that leave`s you with 13 player so automatic a player will come in and always old to give a 14 man squad as you need 11 1st teamer`s and 3 player`s on sub`s bench