Chiefs, Browns among the NFL's biggest disappointments of 2021

The NFL billed this 2021 campaign as the “Biggest Season Ever” given the expansion from 16 to 17 regular-season games. But “The Wackiest Season Ever” could have served as an equally fitting slogan.

As the midway point of the season approaches, the AFC and NFC remain very much open, as no team has managed to take commanding lead on the field, and most divisions are still up for grabs and difficult to predict.

This first eight weeks of the season have featured a few surprise showings from up-and-coming squads, but several teams and players who entered the year with great expectations have struggled during the same period.

There’s still time for some of these clubs or individuals to turn their seasons around, but the clock is ticking – and for some, prospects are dimming.

Here’s a look at some of the biggest disappointments of the first half of the NFL’s 2021 regular season.

Chiefs quarterback Patrick Mahomes

Miami Dolphins

Coming off of a 10-6 campaign, Brian Flores’ Dolphins were expected to contend for a playoff berth in 2021. After heavy investments, the defense should have rounded into dominant form. Tua Tagovailoa should have built on last year’s timeshare action as a rookie and taken his place among the ranks of the promising young quarterbacks in the league.

But instead, the Dolphins own a 1-7 record and seemingly are trending toward dysfunction. A bevy of high draft picks largely have yet to pan out. Rumors of a Deshaun Watson trade has hung over the franchise much of the season, bringing with it needless distractions. Flores, in his third season as head coach, has displayed questionable decision-making both when it comes to his staff and on in-game management matters. An offense on its third and fourth coordinators in three seasons (the Dolphins have co-offensive coordinators in 2021) has little flow and no identity, and the defense has surrendered 29 points and a league-high 406.9 yards per game.

Although regarded as a bright football mind and strong leader, Flores hasn’t lived up to expectations in 2021, and neither has his squad. That means he very well could find himself on the hot seat if the Dolphins can’t pull off a turnaround.

Chase Young

Year 2 for the second overall pick of the 2020 NFL draft should have featured more strides toward achieving the dominant, game-changer potential that the pass-rusher boasts. But instead, Young has seemingly regressed for Washington.

After recording 7 ½ sacks and earning Defensive Rookie of the Year honors last year, Young has only 1 ½ sacks, four QB hits and three tackles for a loss in eight games this season.

Washington coaches viewed Young as the tone-setter for a defense regarded in 2020 as one of the best in the league. But that same unit has regressed right along with Young, giving up 389.4 yards and 28.4 points per contest, and Washington owns a 2-6 record one year after winning the NFC East.

Cleveland Browns

Based on the potential displayed last season when they posted an 11-5 record and reached the playoffs for the first time since 2002, the Browns seemingly entered this season with a real chance to contend for AFC supremacy.

Quarterback Baker Mayfield had a chance to position himself for a big pay day. Odell Beckhman Jr. looked to rebound from a torn ACL and help further bolster an offense loaded with playmakers.

But nothing has gone according to plan. Injuries have plagued many of this squad’s top contributors, including Mayfield, who even when healthy has struggled with consistency. Beckham, meanwhile, has been a shell of his former self with only 17 catches for 232 yards and no touchdowns in six games.

The gritty performances that defined this team last season have been few and far between. The Browns on Sunday fell to 4-4 after losing 15-10 to an anemic Pittsburgh Steelers squad, and the loss dropped Cleveland into last place in the AFC North.

A Cleveland Browns fan reacts to the action late in the game against the Pittsburgh Steelers at FirstEnergy Stadium.

Jamal Adams

After finding a new home with the Seattle Seahawks via trade last season, Adams played well enough to earn himself a four-year, $70 million contract extension that made him the highest-paid safety in the NFL entering this season. The Seahawks were counting on the versatile Adams to make an even bigger impact in Year 2 while anchoring a defense tasked with slowing traditionally high-powered divisional foes like the Los Angeles Rams, Arizona Cardinals and San Francisco 49ers.

Instead, Adams has had a far less impactful 2021 campaign. After setting the single-season record for sacks by a safety with 9 ½ in 2020, he has no sacks this year. Adams also has no interceptions, no forced fumbles and only two pass breakups.

And Adams and his teammates in the defensive backfield have struggled to get on the same page, with the safety also struggling in man coverage. The Seahawks rank in the bottom third of the league, giving up 401.5 total yards and 275.3 passing yards per game. At 3-5, they rank last in the NFC West.

49ers offense

Hit hard by injuries in 2020, the 49ers entered this season with renewed health and the potential to return to the ranks of the league’s contenders. The 49ers offense was supposed to serve as a big catalyst for that success as the unit relied on a talented collection of players, continuity, depth and versatility. Led by one of the brightest offensive coaches in the game, San Francisco also promised excitement as Kyle Shanahan found ways to work athletic rookie quarterback Trey Lance into the mix with veteran Jimmy Garoppolo.

But this unit has yet to find the rhythm, effectiveness and consistency that it has displayed in years past. Garoppolo missed more time with calf injury, as did one of his best weapons, tight end George Kittle. Lance struggled in place of Garoppolo, and instead of explosive, the offense has been average.

After opening the year 2-0, the 49ers went on a four-game slide with tough losses to Green Bay, Seattle, Arizona and Indianapolis. A win over Chicago on Sunday stopped the bleeding, but this unit has more kinks to work out than expected and a lot of catching up to do.

Carson Wentz

Written off by the Philadelphia Eagles and shipped to Indianapolis, the quarterback looked to salvage his career while reunited with Colts coach Frank Reich, who served as offensive coordinator during the best and most promising years of Wentz's career. But Wentz’s time in Indy got off to a rough start thanks to COVID-19 quarantine and then foot surgery.

After a few rocky performances to start the season, Wentz seemed to be finding greater comfort and effectiveness.

But then came Sunday, when Wentz showed little consistency, awful poise and terrible decision-making that ultimately cost the Colts in a very winnable and crucial matchup with AFC South leader Tennessee.

Wentz has talent, and at times he has shown flashes of his 2017 MVP candidate season. But he’s still far too inconsistent, and the Colts could wind up regretting this experiment – especially if they end up having to fork over a first-round pick to the Eagles if Wentz's playing time exceeds 75% of the team's snaps.

Kansas City Chiefs

Maybe the Super Bowl runner-up curse is indeed real, because the Chiefs have looked nothing like the dynasty-in-the-making that the league has witnessed the last three seasons.

The defense is back to its atrocious form, the offensive line moves of the offseason haven’t made as dramatic an impact as hoped, and Patrick Mahomes is struggling to keep this squad afloat as he has since embarking on his MVP campaign in 2018.

The Chiefs barely beat the Browns in Week 1, blew a double-digit lead and lost at Baltimore in Week 2 and then got beat at home by the Chargers in Week 3. Kansas City pulled off victories against lowly NFC East teams Philadelphia and Washington. But shortly after came blowout losses to Buffalo and Tennessee. A lackluster win over the Giants on Monday elevated Kansas City to a pedestrian 4-4 mark.

Believe it or not, the early-season favorites to win the AFC yet again now face the very real possibility that they could miss the playoffs altogether.

Follow USA TODAY Sports' Mike Jones on Twitter @ByMikeJones.

This article originally appeared on USA TODAY: Chiefs, Browns among NFL's biggest disappointments of 2021