Any team's in trouble if loses its ace
I don't think Houston will be in that much trouble. I don't think the Cardinals lose much if they lose Carpenter for 15 starts.
In theory, any team's in trouble if they lose their ace; in reality, some teams find themselves in a lot deeper trouble than others when their ace goes down.
It's my anecdotal observation that "little engine that could" teams need not only talent, but good breaks, to unseat standing powers.