No position in NFL history has been more indicative of the ebbs and flows of offensive trends than tight end.

When Philadelphia's Zach Ertz found himself on an island against New England FS Devin McCourty in the fourth quarter of Super Bowl LII, the Eagles were getting exactly what they wanted. And it’s quite possible, when Ertz planted his foot in the ground, beating McCourty on a slant, catching the ball and leaping across the goal line for the go-ahead touchdown, the TE position reached its evolutionary apex.

The originators of the game never could have envisioned such a scenario playing out on the biggest stage, but the new crop of prospects entering the league are all cut from the same cloth.

This year’s draft presents a host of candidates of the modern day archetype: big, strong, fast, and a threat in the receiving game. This year’s top prospects — South Dakota State’s Dallas Goedert, Penn State’s Mike Gesicki, South Carolina’s Hayden Hurst, Oklahoma’s Mark Andrews and Indiana’s Ian Thomas — represent the new wave that every team has been trying to catch for a while. Versatile pass-catchers at tight end that can play in-line or outside are a rare, desired commodity, but they also may represent a potential problem for the position in the near future: players that are too one-dimensional.

The aforementioned prospects aren’t adept at a skill that was previously a prerequisite for tight ends. They struggle to block, which lends one to ask whether this year’s top prospects are worthy of high selections, or are they simply byproducts of teams trying to shove square pegs into round holes?

A player who was first used ostensibly as a sixth offensive lineman, has steadily been molded and reformed into a devastating offensive weapon that, if used correctly, can alter games.

Thanks to a gentle nudge and reevaluation of the role from coaching pioneer Paul Brown in the 1960s, the tight end has become the most intriguing offensive chess piece of the modern era. But that progression has taken time.

The first great tight ends, like Baltimore’s John Mackey, St. Louis' Jackie Smith and Chicago’s Mike Ditka, weren’t racking up astronomical numbers relative to today’s best, as the game itself was not yet the aerial show it is now. But they were the first wave of guys to make the defense think, “Is this guy going to catch a touchdown over me or knock me on the ground?”

That tinge of doubt now entering defenses minds combined with creative offensive minds wanting to exploit mismatches with athletes entering the league like San Diego’s Kellen Winslow and Cleveland’s Ozzie Newsome made short work of overmatched secondaries.

The rise of West Coast offenses predicated on decision-making and accuracy coupled with the rise of zone defenses brought the need for more refined tight ends who not only needed to maintain their ability to block but also run routes effectively enough to settle into zones and give their quarterbacks windows to hit them. Think Dallas’ Jay Novacek, San Francisco’s Brent Jones and Denver’s Shannon Sharpe.

As the passing game has continued to evolve and become the preferred mode of ball movement, the schematic hi-jinx being played between intelligent coordinators has been elevated. Kansas City’s Tony Gonzalez and Dallas’ Jason Witten were the precursors to the current crop who, while still having the ability to perform the function their position was initially intended for, are more receiver than anything else.

The appeal of players like New England’s Rob Gronkowski, Ertz, and Kansas City’s Travis Kelce is that they create chaos for defense. Their combination of speed, strength and receiving ability make it difficult for defensive coordinators to find advantageous matchups. But the important thing to remember is that they are well-rounded players.

And therein lies the issue. The trend toward strictly pass-catching tight ends at all levels of the game has watered down the diversification of the prospects that makes the position so unique. The desire to find these matchup nightmares in spite of their scarcity has stunted development of dual-threats at the position. It’s entirely possible that we’re not seeing a tight end revolution, but a position at an evolutionary crossroads.

From a supply standpoint, these players are extremely difficult to find. Filling the TE position is already a relatively niche role for high school players who aren’t big enough to play offensive or defensive line and not fast enough to play wide receiver.

College offenses continue to utilize the TE position, but they have trended toward using it not for its dual threat nature but instead to create athletic mismatches. This affects the NFL TE position in two ways. First, when these tight ends are then asked to transition to the NFL game against superior athletes, outside of a few outliers, the mismatches aren’t there. Secondly, they haven’t been asked to develop their blocking to the point where it can pass as anything more than mediocre in the NFL.  This is where college coaches needing to win games to keep their jobs takes the place of proper development of players.

The dual nature of the TE position is what makes it unique. Teams had the luxury of carrying multiple tight ends on the roster, each with the ability to block and catch at the requisite level. Now, those roles have been divided more often that not with one tight end focused on the in-line, more physical nature of the position, the other on the more evolved, pass-catching area. This helps defenses and allows them to key on the bigger threat.

The position is still being used a great deal, even slightly more that it was previously. Based on snap count data from the last five years via Football Outsiders, the number of tight ends used per snap has held fairly steady. In 2012, 1.33 tight ends were used on the average NFL play from various formations. In 2017, that number went up slightly to 1.38, hinting at the creativity in schemes that teams like Kansas City, New England and Philadelphia favor using to create defensive confusion.

But what has changed is the number of snaps taken by top players at the position, hinting at a greater diversification of roles of the tight end in NFL offenses. In 2012, 10 tight ends saw at least 90 percent of their teams offensive snaps, while 16 saw 80 percent.  In 2017, only one saw 90 percent and seven saw 80 percent. Sure, injuries play a role in this, but that's a seismic shift.

Defenses have also begun to counter spread offense and pass-catching tight ends with a group of athletes at the LB and S positions unlike any other era. Speed is now the determining factor at linebacker, as the shift from run to pass has necessitated players like Telvin Smith and Bobby Wagner, or Georgia’s Roquan Smith, who are still stout against the run game but are really there because they are good in coverage and can alleviate any matchup deficiencies.

The use of hybrid safeties, like Deone Bucannon and Mark Barron, or Florida State’s Derwin James and Alabama’s Minkah Fitzpatrick, who are instinctual playing the run but can matchup with tight ends, add to the list of kryptonite for advantageous TE matchups.

A combination of the aforementioned factors could contribute to the drop in targets for top-tier tight ends. In 2012, three players — Witten, Jimmy Graham and Gonzalez — had at least 124 targets. Last season, Travis Kelce led all tight ends with 122.

Have defenses already course-corrected? If teams can counter the evolution at tight end with their own chess pieces, when will the time come when offenses simply replace those tight ends with quicker receivers more adept at route running if they are going to pass anyway? Perhaps sooner than we think.

There is a comparable for this progression at tight end, though probably more extreme.

Like tight end, when the ground game reigned supreme, fullbacks were another bridge between the skill positions and the warfare waged in the trenches. At one time, fullbacks were primary ball carriers in NFL offenses. Then they became secondary until the West Coast offenses asked them to catch the ball much more and players like Larry Centers and Keith Byars racked up the receptions. Daryl Johnston, William Henderson and Lorenzo Neal are just a few examples of players around the same time who weren’t asked to handle the ball as much, but who were essential to a well-functioning ground game.

Now, fullbacks are almost extinct as teams trend toward one-back power schemes or utilize their RB2 role for speedier pass-catchers like Duke Johnson, Theo Riddick, or James White.

Could the next shift be moving away from tight ends completely? Probably not. About 60 percent of snaps in the NFL are taken with 11 personnel (one tight end, one running back) and about 90 percent of snaps occur with at least one tight end on the field.

The more likely next step is this: defenses continue to find ways to eliminate any matchup advantage tight ends have as pass catchers. Offenses begin to wise up and realize the confusion caused by having a more well-rounded tight end that can be a factor in both the ground and pass games. Balance creates confusion, and more so than ever, that’s the way to get the best of defenses that are smarter and more creative than they have ever been.

It’s an amazing thing to see players like Gronkowski, Ertz and Kelce play tight end the way they do. But it’s also important to remember they are unicorns, exceptions to the rule not easily found and not the template for which teams should be searching long and hard for.