samthegooner and Big Willie , you are referring to two different processes
1) Transfer agreement: this is agreement of a transfer amongst the player and his new/old clubs. This can happen at any time of the year. Even in February or March
2) Registration: this can only happen during specific dates, what we typically refer to as 'the transfer window'.
Now that most domestic seasons are over, teams are stepping up transfer agreements, and they will register players during the 2 windows this summer
