We can trade picks in one of my leagues. It's a 5x5 keeper league, where you can keep up to five players per season. You can hang onto a keeper for up to five years, and if you trade a player, their "contract" goes with them. For example, if I've had Ellsbury for two seasons as a keeper and I deal him, the team that acquires him can only keep him for three more seasons. Also, for each player you keep, you lose a pick off the front of the draft, so if you keep three players, you lose your first three picks. When trading draft picks, you are not allowed to acquire someone's pick in what would amount to a "keeper" round for you. For example, if you are keeping three players, you are not allowed to trade for anyone else's first, second, or third round picks. Similarly, they can't trade any of their "keeper" round picks away. Also, the amount of picks you are sending away must equal the amount you get back.