The life of an NFL fad can be brutish and short. This one, which seemed so full of life only a year ago, has been rudely cut down just seven weeks into the season, the victim of premeditated first-degree smothering by NFL defensive coordinators.

We're talking, of course, about the golden age of the tight end.

Kansas City safety Eric Berry defends San Diego tight end Antonio Gates. Getty Images

Last season, Rob Gronkowski of the New England Patriots, a tight end who is built rather like two elephants duct-taped together, had 1,327 yards—the sixth-most among all players in the NFL. If you listened closely, you could hear the sound of Tim Tebow posters being ripped off bedroom walls and replaced by Gronkowskis. You could hear the giddy cries of fantasy football team managers who eagerly cried "I'll take Gronkowski!" in the early rounds of their fantasy drafts.

While Gronkowski is once again the league's top tight end, he's only No. 24 in receiving yards. Overall, only three tight ends are in the top 40 in the NFL in receiving, down from seven at the end of last season.

The change, mostly, is brought upon by a subtle change in defenses. Coordinators quickly realized that the reason tight ends were so successful last season is because they were able to outrun linebackers and, after doing so, run over the Lilliputian defensive backs charged with trying to stop them. They realized, collectively, that they had to find a way to put more players on the field who were faster than linebackers but also larger than the typical speed-specialist cornerback.

Flipping through the list of players, they appear to have stopped on the page devoted to safeties. This season, in an effort to squelch tight ends, The Green Bay Packers, New England Patriots and Detroit Lions all have three safeties, rather than two, who have played more than 25% of their team's defensive snaps, according to Pro Football Focus.

The safety, a generally overlooked position with plenty of value but very little flash, is typically slower and larger than a cornerback but faster and smaller than a linebacker. Their usual job description is to work in pairs, splitting the field in half and covering their portion by roaming around with no specific assignment.

It helps that the typical safety coming out of college isn't so pokey anymore: Ten safeties in the last seven NFL combines have run times faster than 4.5 seconds in the 40-yard dash.

"The better you can make matchups in this league, the more effective you'll be, so if you have safeties that can run and cover but also come up and hit people, of course you'll want those guys in the game to neutralize [running quarterbacks and tight ends]," said Redskins linebacker Lorenzo Alexander.

During Sunday's game between the Houston Texans and Baltimore Ravens (the owners of a lethal two-tight-end attack), the Texans trotted out safety starters Danieal Manning and Glover Quin for each of the game's 61 snaps. For 28 of them, however, backup strong safety Troy Nolan joined the party as a third safety. it seemed to work: Nolan didn't give up a completion on 28 snaps of coverage.

Likewise, the New York Jets, facing Gronkowski, also threw three safeties at the Patriots Sunday—Yeremiah Bell and LaRon Landry played on all 80 snaps while Antonio Allen added additional bulk on 13 plays.

Chiefs coach Romeo Crennel said the safety position has been caught up in an ongoing chess match between offenses and defenses. It's not just that tight ends are catching more passes, he said, it's that they're also doing some of the other dirty chores—like lead-blocking on runs. Put a safety out there and you may neutralize the advantage, he said. Unless, of course, the safety isn't fast enough. In that case, he said, "you're putting them in positions where they're probably going to fail."

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