2) The return often looks good only on paper.
As the Philadelphia Phillies built their World Series rotation through trades — Roy Halladay, Cliff Lee, and Roy Oswalt — they parted with many of their top prospects. Over five years removed from all of those wheelings and dealings, only two of the players the Phillies traded away — Carlos Carrasco and Travis d’Arnaud — are having a big impact on a big league roster. It took both a while to blossom. Kyle Drabek was the centerpiece of the Halladay trade. When was the last time you heard Drabek’s name read by a big league announcer?
The Nationals do have a need to reload their farm system with big-league-ready position player talent, but trades for prospects come with very few guarantees and often turn out lopsided in favor of the team that traded for the ace. Additionally, a team like the Boston Red Sox may be unwilling to part ways with a huge package of prospects given the fact that Strasburg can bolt at the end of the year.