Yea, the club are knwon for getting their replacements in fast.
Ulloa
Buckley
Bridcutt
Barnes
I should imagine it's virtually impossible to get a replacement first? Firstly because the negotiations with the selling club will be just as difficult as those with the buying club. Secondly you can't really make an offer for a player on the condition that one of yours is being sold. Say we go to Oldham, for the sake of argument "Will you accept £2m for your up and coming centre back (by the way we're not sure if we want him or not?)"