It seems when I make an offer on certain players in the summer of 2011 and he accepts my contract, that they will join my team in summer 2012. But I need them this season already . Can u see somewhere, which players only join in te next season?
Maybe they're under 18. Most countries don't allow their player leave country under 18. For example you can sign Carlos Fierro from Mexico and he is 16/17 but won't be able to join until he is 18.