Prospects aren't worth what they used to be in trades. Three years of Yordano Ventura isn't likely to be cheaper in trade than 3 years of Tyler Thornburg, who netted a major leaguer and a prospect ranked ahead of nearly every name on that list. And the Astros of all teams are well aware of the cost of young, cheap, controllable closer, having surrendered 5 players (including MLB-ready pitchers Vince Velasquez and Brett Oberholtzer) for Ken Giles one year ago yesterday...