FanGraphs just can't let us sleep easy:
There's a good chance that, in the next two seasons, Wandy Rodriguez, Carlos Lee, Hunter Pence and Michael Bourn will likely join Oswalt and Berkman on their way out to make room for new blood -- and Houston will have pick other players to build the franchise around. Can the core they have already assembled lead them to the playoffs, or possibly a championship? Based on the current core, it appears unlikely...
...You build championship teams through a combination of stars and role players -- look at any recent World Series winner for documentation of this -- and the Astros currently have the role players, but not the stars. GM Ed Wade is going to have to draft carefully for the next few years, or this rebuild will take a long time. He needs to develop a few star-caliber, quickly-rising-through-the-minors guys out of the draft to complement the players above.
And in between, they break down - and not in a good way - virtually every Astro under 30 save for Bud Norris.