The Cubs current front office of Theo Epstein and Jed Hoyer had traded away players before in which they were required to pay part of the salary of the player being traded away. But neither of those players were ones that Theo and Jed personally acquired.
One of the first things that Theo and Jed had to do when they took over the Cubs is figure out what to do with a disgruntled Carlos Zambrano. They ended up trading Zambrano away to the Florida Marlins.
However, that trade was financially complicated. The Cubs had to agree to pay $15 million of the $18 million Zambrano was owed for the 2012 season.