One of the lasting images from the past few seasons is Detroit Lions wide receiver Calvin Johnson standing at the line of scrimmage and being covered by two New Orleans Saints defenders.
It was only the second quarter and the Saints had a 17-point lead at that point in the game. It was simply a startling image.
How many wide receivers, a position that's regularly viewed by the NFL's best teams as disposable and easily replaced, can say they were literally double covered to the point where they couldn't get off the line of scrimmage at such an early point in a game?
Incredible, absolutely incredible. Johnson is the NFL's ultimate matchup nightmare on the offensive side of the ball. On the opposite side of the line of scrimmage, it's DeMarcus Ware of the Dallas Cowboys.
Ware, the longtime defensive end and outside linebacker, is a pass-rushing menace who terrorizes offensive linemen and quarterbacks on a regular basis. He's had at least 11 sacks in seven of the last eight years, can cover very well for his size and lines up all over the trenches.
Between Ware and Johnson, football coaches have their work cut out for them every Sunday. Johnson, in particular, is dangerous because he can line up all over the formation and do damage. Recently, he's added the ability to play in the slot in addition to the perimeter, making him a very difficult matchup for defenses.
The reason he's so problematic from the slot is because of his combination of size, speed and route-running. He grades off the charts in all three areas, measuring in at 6'5", 236 pounds. However, he breaks down in his routes like he's 6'1". In addition to the three above, he has quick feet that can deceive safeties, as New Orleans Saints safety Malcolm Jenkins found out during the 2012 playoffs.
Johnson was in the left slot on the short side of the field. Before the snap, the Saints looked to have him bottled up because they were playing Cover 2. Jenkins was over the top of Johnson and the outside cornerback would be underneath him following the snap.
At the snap, Johnson ran directly at Jenkins and then looked back to the quarterback. That, along with a quick jab of the right foot, was a part of selling the route. Both led to Jenkins taking false steps in the wrong direction and falling behind in coverage.
In addition to Jenkins' missteps, the cornerback failed to sink deeper into the flat and as a consequence, Johnson beat the two for a touchdown in the corner of the end zone.
It's plays like these that make it difficult to cover Johnson, who spent 30 percent of his snaps in the slot in 2012, according to Pro Football Focus.
Another example of his success from the slot came against the Atlanta Falcons in Week 16.
He was lined up as the slot receiver in the Lions' stacked twin set to the left side of the field. He was set to run a dig route against the Falcons' exotic defense, which featured cornerback Dunta Robinson covering Johnson outside and a late rotating safety inside.
When the play began, Johnson ran vertically for roughly 10 yards before sticking his right foot in the ground and running to the middle of the field. By that time, the aforementioned defenders were in position to box him out and prevent a catch.
However, a well-run route by Johnson changed that. He ran a sharp and narrow route across the middle, not giving either defender a chance to intersect him.
With the defenders out of position, Johnson reached sky-high to haul in the pass.
Whereas Johnson is difficult to defend from the defense's view, the Cowboys' Ware is difficult to defend from the offense's perspective.
It's not easy to find blocking schemes that can protect against Ware. He's a very intelligent defender and understands how to attack the line. He's exceptionally quick and powerful as well, making him the complete package as far as pass-rushers go.
Under the direction of then-defensive coordinator Rob Ryan last season, Ware was moved around all over the field and did damage against tackles, guards and centers. Now with Monte Kiffin running the show, he's expected to be primarily a defensive end, which isn't necessarily a bad thing.
In Kiffin's Tampa 2 scheme, Ware will once again be a weak-side rusher and his primary focus will be getting after the quarterback, which he didn't always do under Ryan.
Because of the switch to defensive end, Ware will have more opportunities to jump snap counts and beat tackles with his wicked first step, like he did against the Cleveland Browns' Joe Thomas.
It was early in the third quarter of a Week 11 game against the Browns. Ware was lined up at outside linebacker on 3rd-and-8 and with the play clock winding down, he jumped the snap to get a leg up on Thomas.
Ware's early step gave him a great advantage over Thomas, who was still in his stance when Ware crossed the line of scrimmage.
The quick first step set up a power rush off the edge, which consisted of Ware sinking his left shoulder and using his left arm to keep Thomas at a distance. This enabled him to turn the corner and sack quarterback Brandon Weeden.
It was the same type of play that Ware executed against the New York Giants in 2012, when he also came off the line before anyone knew they had to move.
Whenever he has the chance to take advantage of his first step, he uses the same long left arm mentioned earlier to turn the corner and get to the quarterback.
It's no surprise that Ware has quick feet, high IQ and great physical skills. After all, it's the makeup of great players such as himself and Johnson. They are the league's best at their positions and have been playing at a high level for many years.
That's why they give headaches to coaches every week.