The European transfer market is open between the end of the season and 31 August, and again for a short period in midwinter, the 'transfer window'.
During the transfer window clubs buy replacements for players who have suffered injuries or strengthen their squads in preparation either for an attempt to advance in a tournament or in anticipation of an upcoming struggle against relegation.
[3] Financial pressures placed on lower league clubs have led to an increase in the number of PFA members being out of work.
Due to the public nature of transfer requests, they are often used by players to air their grievances, such as frustration over contract negotiations[5] or a clash of personality with the manager.
[8] Since the Bosman court cases, players can leave their club at the end of their contract without having to pay a fee.