The 2015 Astros are going to look drastically different than the 2013 Astros. Now whether all those prospects will pan out or not...
In addition, the Astros are not actually a small market team and have plenty of room to bulk up the payroll if a reasonable option presents itself. Hopefully they don't go the Angels/Marlins route and simply buy whatever happens to be available at the time they decide to spend the money.