I think the FIFA rules state that players without a contract can join any club at any time. I am not sure or they are also directly illegible to play, or that you have to be on the roster on beforehand. read more
The top two clubs in the Championship, which is the division below the Barclays Premier League, are promoted every year, along with the team that wins in the end-of-season ‘play-offs’. They replace the three clubs that finished at the bottom of the Barclays Premier League. read more