[Rain Man]

We don't allow transactions in mid-season for several reasons.

1. Since you already know when injuries will occur, allowing transactions makes it easy for people to work around them, which isn't realistic.
2. It allows us to stock up for free agency the following season if all the good surprise players don't get picked up midseason.
3. This may be my personal nitpick, but in fantasy leagues there are 8 million transactions and the advantage often goes to the fastest person. We want this to be more about roster building than about who can run to the waiver wire and grab someone the fastest. In this game, you better be able to draft well and spend your free agent money well.