The Cowboys have their Posse (or 11) personnel on the field (three wide receivers, one tight end, one running back) in a Doubles Slot formation with running back DeMarco Murray offset to the open (weak) side. The Vikings counter with their base nickel sub-package (five defensive backs) playing Cover-2 in the secondary to defend the four verticals concept.
With the backside guard pulling, and Murray on the inside zone run action, the Cowboys want to sell the play pass to force Vikings' middle linebacker Erin Henderson to attack downhill — opening up the inside vertical seam for Witten.
In Cover-2, the middle linebacker has to match/carry No. 3 (Witten) in a Doubles Slot formation on the seam route. However, Henderson bites on the play fake and vacates the zone in the middle of the field. That allows Romo to target Witten immediately on the vertical release.
And with the two deep half safeties occupied by vertical concepts to the closed (strong) and open sides of the formation, Witten can stem his route in between the hashes to find the hole in the zone coverage.
Both of the Vikings' safeties overlap the throw to the middle of the field, but this isn't their play to make in Cover-2. Henderson never recovers versus the seam route and Witten can finish this play for six points.
On Monday night, Bostic's run/pass keys in Cover-2 will be crucial when the Cowboys move the ball into the red zone. He has to show the ability to read high-hat (pass) versus low-hat (run) and match to Witten on the seam route. It will be a good test for the rookie on the national stage.