From General Manager rg2247: With our new DC Wade Phillips switching to the 3-4 defense, we have lots of peices to acquire. Probably our biggest need, is a Rush OLB, as we currently have just one player on our roster (Connor Barwin) that fits the position well. Aldon Smith is a beast at rushing the QB, & even though he still has a lot to learn, he is young & has incredible potential. This pick came down to Aldon, or a five-technique DE, but with several possibilities at DE, already on our current roster, we felt that Aldon was the right pick for us at this pick.
From the Commish
Sayre: This is a decent pick for the Texans. Smith has a ton of upside, and could most certainly play higher than his draft status winds up being, but this is just an okay pick for the Texans for me. Aldon Smith didn't show exceptional athleticism at the Combine, but he's got a great frame and in Wade Phillips' defense could develop into a very strong player.
The Texans' next best alternative to covering up the worst pass defense in the NFL is to improve their pass rush drastically, and this move on paper gets that done.