Despite a game full of horrible officiating against the Titans, Tennessee found themselves right in the thick of a winnable game in overtime. Indy got the ball to start overtime, and the second play from scrimmage was a total disaster. Following a penalty to begin the drive, the Colts had a 1st down and 10 from their own 29.
Let's start with what you don't see above. The Titans are in their Big Nickel. Reggie Wayne has just motioned from the right side of this still to the left side in the still. Mouton is in the slot covering him. McCourty and Verner are on the outside. I can't say for sure, but I'd guess that RoJo and Babineaux are in a two high look over the top. Michael Griffin is in the box. Our Mike LB, McCarthy, has moved to the outside for an overload blitz.
First things first, let's look at one of the most fundamental things in football: Gaps. More aptly, gap control. When you talk about gap responsibility, this is what is being referred to. Gaps can be seen above. "A" is between the C and G. "B" is between the G and T, and so on.
In a traditional 4-3 look, you're typically going to have LB's maintaining gap responsibility for one or more of these gaps. Further, there are going to be times where one player is responsible for two gaps. This happens often to LBs who will read, react, and attack the correct gap. What should never, ever, happen is that each A gap should be left unaccounted for, which is exactly what has happened here. How did it happen?
The Titans line up in a defensive front designed to pressure the QB. Both DTs are in a 3 Technique. That is, they are going to shoot the B gaps and get up field. (Typically in a 4-3, one of the DTs is on a 0 or 1 technique (over center or shading his outside shoulder), which accounts for one or both of the A gaps.) Morgan is going to attack the D Gap, which more than likely leaves Griffin responsible for the C Gap in a run play here. To the weak side fo the field, Wimbley and McCarthy are both overloading the C Gap. What Gray is trying to achieve here is an overload to the weak side. There are three rushers and only two linemen. And that'd be fine - if it were 3rd and 18. On 1st and 10, this play call is totally non sensical. And, the Colts call the perfect play to exploit this alignment.
*One thing to note before I get into this, I don't know Griffin's responsibility here. I'd guess it's some sort of short zone responsibility, or man coverage on the TE. It's possible Griffin could be responsible for the A gaps here, but unlikely given his alignment. Not that it matters. A Safety shouldn't be the primary run defender on a run down in the first place.
The Colts call a basic trap play. The strongside guard and center down block, seemingly letting the DT run free. Simultaneously, the weakside guard pulls and seals off the penetrating tackle, thus trapping him. It's one of the oldest plays in football, and one taught at the lowest levels of football. Which isn't to dismiss the power of the play. There's a reason it's been around this long. It's a powerful concept. Against a defense with no MLB, and two 3 tech DTs, running this play is like stealing.
You can see here that the weakside guard begins to pull, which the strongside guard lets the DT get upfield.
Trap. The center is now pushing the weakside tackle upfield, while the strongside guard has now moved to seal Wimbley. To Wimbley's credit, he read the play in the backfield and worked to make a play on the ball, he just happened to be put into an impossible situation by a horrible playcall.
19 yard gain.
This one was a real head scratcher. Why you'd trot out essentially dime personnel against "11" personnel on 1st down is questionable to begin with. Then, pulling the MLB out of the middle of the defense to rush the edge while both DTs are in 3 techniques? Why?
The only thing I can gather is that Gray views every play as binary. Pass. Run. Win. Lose. It's like he's playing Tecmo Bowl, and on this play he's guessed pass. Wrong guess Jerry, and while this wasn't the play that lost the game for the Titans, it was certainly deflating.