Glover Quin jammed Blackmon off his route, causing an incomplete pass.
What happened to Justin Blackmon?
Then they started playing games that count.
In Week 1 against the Vikings, Blackmon was quiet, but at least made the stat sheet, with three catches for 24 yards.
In Week 2, he was MIA. With no catches on four targets, his absence of production crippled an offense that generated a franchise-low 117 yards.
The first throw to Blackmon was batted down at the line of scrimmage, so there's not much to learn from it. The play of the Houston front four was so strong that most plays didn't have time to develop.
Note this early sack of Blane Gabbert. The Jaguars send five men out into the pattern but can't manage to get anyone open.
By the time the pocket breaks down, the Texans have everyone covered, including all three deep receivers, with three corners and two safeties. The pocket simply can't hold long enough for anyone to break free.
Even when Gabbert did have time, the Jaguars' route design left something to be desired. On the second incompletion to Blackmon, the wideout goes in motion before the snap.
Notice that when Blackmon moves, the corner responsible for him is Johnathan Joseph, unquestionably one of the best cover men in the NFL.
This is the result.
The pass is offline, but that's a good thing. Had Gabbert actually hit the target, it could have been a pick-six the other way for Houston.
The Texans were physical with Blackmon. On this play, Glover Quin executes a perfect jam on Blackmon four yards off the line of scrimmage.
The contact, which is perfectly legal within the chuck zone, drives Blackmon off his route and disrupts his timing on the play.
Finally, the Texans shut Blackmon down using a cushion. Kareem Jackson feints as if he's going to press Blackmon but retreats just before the snap. As Blackmon accelerates, Jackson has the necessary cushion to stay with him and is all over the play when the ball arrives.
Blackmon's struggles against Houston were a perfect storm of bad line play, an off-target quarterback, some incredible defensive efforts and possibly some uncreative routes.
By far the biggest factor was the stellar play by the Houston secondary. The Texans changed the way they covered Blackmon from play to play, shifting players and giving him different looks throughout the game.