I'm often asked in weekly chats on the site to name the best prospects who will be traded this month. I'll toss out a few names outside of the top 20 - Jonathan Singleton, Yonder Alonso, Robbie Erlin. But the reality is that most buyers are holding on to their top prospects tightly.
ESPN's Buster Olney surveyed team executives, and several feel that the buyers are "exponentially more protective of their prospects." Some teams operate in fear of even marginal prospects becoming useful big leaguers down the line. An NL assistant GM said to Joel Sherman of the New York Post, "top prospects are totally overvalued and have never been tougher to pry away even in a perfect deal."
Still, last summer we saw Justin Smoak, Tyler Skaggs, Wilson Ramos, Brett Wallace, and Anthony Gose dealt, though those last two were for each other. Other good young players such as James McDonald, Jarrod Saltalamacchia, Yunel Escobar, Mark Melancon, and Dan Hudson were traded as well.