1. The play is a play-action zone play to the left.
2. The Texans use their 3 TE set in order to bring one of the safeties and the weakside CB near the line of scrimmage.
3. The play-action towards the CB freezes the CB and forces him to be ready to play the run near the line of scrimmage.
4. Andre Johnson is the line WR and he is running a go route which occupies not only his CB but also the attention of the FS who sees Schaub roll in that direction and look towards Andre.
5. TE Dreesen drags across the field to get the attention of the ILB (Willis) and the SS who both cover his underneath route.
6. Owen Daniels runs a corner route which is open because the FS is floating towards Andre while the CB is trailing the play because has bit on the play-fake that the Texans ran at him which forced him to look run first.