You don't get a good player for nothing. If all your willing to offer is crap you get Jason Marquis.
Wandy Rodriguez would have been better. How many of these "top prospects" actually become a big league regular. Anybody remember all the threads about how Conner Jackson and Carlos Quentin were gonna save the franchise?
The team is still trying to rebuild it's system the fact that they are in contention is just a bonus. They are more than 1 player away from WS contention and they could quite possibly win the division with what they have.
If the team isn't going to compete with the big spenders in FA then the only chance they have at competing is through player development.