The dagger concept is a major concept at the NFL level. It has great value because it is an excellent route vs man and zone. It is highly effective vs. both coverages. Some great qbs such as Rivers, Brady, Mahomes, Wentz and Stafford have made a nice living off this concept.
First the route concept
The route concept is a play side dig by #1 and a post by #2 to run the safety out. The shallow cross comes from the other side with the other wr with him usually running a vertical corner/deep out route followed by the shallow cross. You will often see teams stack the 2 wr to help get an off man situation like the Eagles do below.
Advantages of the concept:
1. It is good against any zone: cover 2, cover 4, 6 or cover 3 variations. The read is the same, read the alley player(curl, flat defender. You read the dig to the shallow. It is also effective vs cover 1 defenses.
2. The safeties and cb are taken care of by the post or skinny post by the #2 wr and this opens the dig window.
3. It is excellent vs man as most teams will run it vs some type of stack formation. This usually creates some type of soft coverage and again the reads are the same.
4. It is a great route to run with 6 man protection. You can handle most 5 man pressures and the shallow cross is a great man beater if it's a 5 man pressure with man principles. There is no sit down and he usually can get open on the crossing route.
5. When you hit the shallow it allows the wr to catch the ball full speed with room to make more plays in the open field.
Again the route concept below
The reads are the same for both which makes this route so hard to defend.
VS COVER 3
The Patriotts come out in 12 personnel and the Raiders go cover 3 with the single high. The great playaction opens the window for the shallow cross.
Easy read on the shallow
Nice read and completion.
Nice job as the dig is open as well as the shallow but makes the right read.
TE is getting open.
WR gets a great release.
Dig isn't there so take the shallow.
good concept and completion.