One of the two moves the LA Angels made was to trade set-up man and fill-in closer Joe Smith to the Chicago Cubs. In return the Angels got a low level minor league prospect named Jesus Castillo who has a tremendous upside. You never know exactly what your getting when you acquire a prospect that is only in Single-A like Castillo, but it was worth the risk for the Angels for two reasons.
The first reason is that if the Angels kept Joe Smith until the end of the season they would have gotten nothing in return as Smith will be a free agent at the end of the season.