Five years ago, I surveyed the many changes brought to the tight end position during the era of Tony Gonzalez and Antonio Gates, whose parallel ascents to the top of the historical rankings mirrored the game’s turn toward more receiver-like talents in the role. During the 15 NFL seasons from 1999 to 2013, either Gonzalez or Gates finished among the top five in tight-end receiving yardage every single year. During that same span, the share of league receiving yards going to tight ends increased dramatically, from 12 percent to 21 percent.

It was a tight end revolution. But by now, the primary instigators have moved on. Gates is sort of still around — maybe — but Gonzalez retired after the 2013 season. And Rob Gronkowski, the greatest tight end of the era after the primes of Gonzalez and Gates, hung up his spikes in March. In their place, new statistical monsters have emerged. In fact, 2018 saw both of the two greatest yardage seasons by tight ends in NFL history:

The best tight ends of 2018 covered lots of ground … Most single-season receiving yards by a tight end in NFL history, 1920-2018 RK Player Year Team Games Catches TDs Yards 1 George Kittle 2018 SF 16 88 5 1377 2 Travis Kelce 2018 KC 16 103 10 1336 3 Rob Gronkowski 2011 NE 16 90 17 1327 4 Jimmy Graham 2011 NO 16 99 11 1310 5 Kellen Winslow 1980 SD 16 89 9 1290 6 Tony Gonzalez 2004 KC 16 102 7 1258 7 Todd Christensen 1983 LRD 16 92 12 1247 8 Jimmy Graham 2013 NO 16 86 16 1215 9 Jackie Smith 1967 STL 14 56 9 1205 10 Tony Gonzalez 2000 KC 16 93 9 1203 11 Pete Retzlaff 1965 PHI 14 66 10 1190 12 Rob Gronkowski 2015 NE 15 72 11 1176 13 Ben Coates 1994 NE 16 96 7 1174 14 Tony Gonzalez 2007 KC 16 99 5 1172 15 Kellen Winslow 1983 SD 16 88 8 1172 16 Zach Ertz 2018 PHI 16 116 8 1163 17 Antonio Gates 2009 SD 16 79 8 1157 18 Todd Christensen 1986 LRD 16 95 8 1153 19 Jason Witten 2007 DAL 16 96 7 1145 20 Travis Kelce 2016 KC 16 85 4 1125 Source: Pro-Football-Reference.com

After producing an eye-popping 2,713 yards between them, George Kittle of the San Francisco 49ers and Travis Kelce of the Kansas City Chiefs are clearly the new standard-bearers for the superstar tight end. So is this the start of another Gonzalez/Gates-style dynasty at the position? Or something different entirely? And might they be joined by even more elite tight ends in 2019?

There’s no question that the stat above — a record-breaking double for single-season yardage — grabs your attention right away. But it doesn’t necessarily follow that Kittle and Kelce had the two most valuable tight end seasons of all time last year. According to Football Outsiders’ Defense-adjusted Yards Above Replacement metric, which measures a player’s production in terms of how much it adds to the team’s chances of scoring on any given drive (and adjusts for strength of schedule and era), Kittle was only the 44th-best single-season performer at the position since 1986, their earliest season of data. And instead of being the second-best all-time, Kelce ranks 60th, while Philadelphia’s Zach Ertz, who last year posted the 11th-best season for a tight end since 1986 in terms of yardage, ranks just 282nd in DYAR.

… but they don’t look as great by other measures Defense-adjusted Value Over Average (DVOA) and Defense-adjusted Yards Above Replacement (DYAR) for tight ends with the most receiving yards in a single season since 1986 Yards Rank Player Season Team DVOA DYAR DYAR Rank 1 George Kittle 2018 SF +15.1 207 44 2 Travis Kelce 2018 KC +11.5 196 60 3 Rob Gronkowski 2011 NE +45.9 459 1 4 Jimmy Graham 2011 NO +16.6 244 22 5 Kellen Winslow 1980 SD — — — 6 Tony Gonzalez 2004 KC +26.1 335 8 7 Todd Christensen 1983 LRD — — — 8 Jimmy Graham 2013 NO +15.7 223 35 9 Jackie Smith 1967 STL — — — 10 Tony Gonzalez 2000 KC +27.7 357 4 11 Pete Retzlaff 1965 PHI — — — 12 Rob Gronkowski 2015 NE +21.0 235 30 13 Ben Coates 1994 NE +15.9 223 35 14 Tony Gonzalez 2007 KC +9.4 161 97 15 Kellen Winslow 1983 SD — — — 16 Zach Ertz 2018 PHI +1.6 93 282 17 Antonio Gates 2009 SD +35.6 336 7 18 Todd Christensen 1986 LRD +21.4 274 13 19 Jason Witten 2007 DAL +19.6 242 26 20 Travis Kelce 2016 KC +26.0 261 17 DVOA is Football Outsiders’ measure of per-play efficiency, scaled as a percentage relative to average. It is used to generate DYAR, which measures total value relative to a backup-level player. Advanced metrics are only reported for 1986 and later. Source: Football Outsiders

While the best yardage seasons by Gronkowski, Gonzalez and Gates ranked among the most valuable since 1986 according to DYAR — thanks in large part to enormous per-play efficiency (as measured by Defense-adjusted Value Over Average, Football Outsiders’ rate-stat answer to DYAR) — Kittle and Kelce were less efficient in their monster seasons. This is true relative to other tight ends but also just in the sense that all passes to a tight end are less efficient now than they used to be, both compared with the average pass and (especially) relative to the average offensive play.

From 2006 (the first season of ESPN’s expected points added data) through 2011, the average pass attempt to a tight end added about 18 percent more EPA per play than the overall average for all passes. Since 2012, the average tight end target has been worth only 14 percent more EPA than an average pass to any position. At the same time, passes make up a larger share of offensive plays than in the past, which only further reduces the edge in effectiveness that a tight end target has relative to the average NFL offensive play.

Simply put, it’s harder to stand out as a great tight end these days. Gonzalez and Gates used to excel by creating mismatches, forcing defenses to choose between committing undersized defensive backs against their towering frames or using slower linebackers in coverage against their speed. But defenses have adapted by emphasizing quicker linebackers and developing hybrid safeties who can defend the run while still keeping stride with receiving tight ends. At the same time, tight end prospects are emphasizing pass-catching skills more than other aspects of the job, creating a whole league full of quasi-receivers at the position.

You can see this trend in how tight ends are being deployed. Only 44 percent of total receiving yards went to tight ends who lined up from the traditional tight end spot at the end of the offensive line (including playoffs). Kelce picked up 906 yards from lining up as an oversized slot receiver, and 41 percent of overall tight end receiving yardage was gained that way in 2018. Kelce also hauled in 240 more yards — best in the league among TEs — while split out wide, from where about 13 percent of all tight end yardage was accrued. (That’s nearly double what the share was at the beginning of the decade.)

Perhaps the balance of all these changes explains why, after massive gains in the share of receiving yardage filtered to tight ends between the 1990s and early 2010s, that number has stagnated in recent seasons, fluctuating between 19 and 20 percent each year since 2013. Tight ends are still among the most efficient options on the field, but teams might be maxing out just how much of a receiving load they can ask the position to carry. Ertz set a new tight end record last season with 156 targets; Kelce (150) and Kittle (136) weren’t far behind.

The next tight end to join them atop the yardage (and workload) list might be O.J. Howard of the Tampa Bay Buccaneers, who ranked third in DYAR behind Kittle and Kelce last season despite being targeted for a third as many passes. Howard had a league-leading DVOA of +44 percent in 2018, and he actually ranked ahead of Kelce in ProFootballFocus’s metrics because of superior blocking grades. Howard seems due for a greater role in Tampa’s offense than before, though, and if his elite TE peers are any indication, that might mean a big dip in efficiency. Then again, Howard also embodies the kind of deep-threat mismatch a modern tight end is increasingly required to be, with an average depth of 11.47 air yards per target last season, which ranked second only to Gronkowski.

Either way, despite the record-setting numbers, Kittle and Kelce aren’t necessarily better than their TE predecessors — just different. And they might have company at the top soon. But if today’s top tight ends are less dominant relative to league average than in the heyday of Gonzalez and Gates, it might just be because the whole position has gotten better and is being asked to do a lot more, while defenses are more geared to stop them than ever.