Will Carroll, formerly of Baseball Prospectus and current Sports Illustrated writer, made his bones in the industry by writing about injuries. His Under the Knife column got him noticed by Peter Gammons and he's taken off since then. He's done a heck of a job making writers and fans understand what injuries mean and how severe they are.
That's why we should be looking at his Team Health Report over at SI. It's important, but I also think it isn't. For instance, Astros County has a pretty good take on the article, but I just don't believe that if those red light guys get hurt, it spells the end of this season. AC has been known to be snarky a time or two, but I don't think that's the case here (AC, let me know if I'm wrong).
Of that list of seven guys, only three of them would set this team back with an injury. Jason Castro, Brett Myers and Wandy would be hard to replace, but not impossible. An injury to Castro would do more to set back the team in future seasons than anything this year. The Astros probably can't find the production they did from Myers and Wandy in the minors or on the waiver wire.
But, the other guys? Happ is probably replaceable, as is Norris. Lyon, as I detailed in this post, is probably the most replaceable cog on the team. And Carlos....oh, Carlos. An injury to Lee might hurt the team in terms of power. But, would the upgrade in defense from Michaels starting every day or platooning with Bogusevic even things out? Most assuredly.
Losing all those guys would dramatically shift the makeup of this team, but I don't think it's the end of the world. In fact, in some cases, it might actually improve the team (if J.D. Martinez and Jordan Lyles got called up to replace the injured guys).