The Colts were expected to have an improved pass rush. Adding a guy like Justin Houston at defensive end was supposed to help increase their front four rush. It has, but not because of Houston. A lot of their sacks have been helped by solid play in the secondary.
There have been 8 sacks by the defense so far. Of those sacks, only half of them can be attributed to blitzes or the front four getting penetration. The other half is because of great coverage down the field that didn’t allow the quarterback to throw the ball anywhere.