Without fail, every offseason we hear talk about the “Super Bowl hangover.” You know, this refers to how hard it is to retain those newly in-demand free agents on the open market. How difficult it is to play with a target on your back every week. How those extra games are going to catch up with you next season. How, for mainly intangible reasons, winning the Super Bowl will make you a worse team the following year.

The Broncos won the Super Bowl last year, and this year — well, they’re just not as good. It’s been a down year in terms of quality at the top of the league, but the defending champs haven’t been able to capitalize on that.

Related The Winners and Losers From NFL Week 14

Sure, Denver is still in line for the AFC’s sixth and final seed at 8–5 after losing 13–10 to the Titans on Sunday, but the loss was a microcosm of their struggles all season. With Trevor Siemian providing significantly improved play at quarterback this year compared to what we saw from Broncos signal-callers last season — he threw for 334 yards and a touchdown on 69 percent passing against Tennessee — you’d have expected Denver to reach new heights and only increase its dominance, especially since most of the key contributors returned from 2015’s elite defense. But instead, a suspect rush defense, an inept run game, and inconsistency late in games have been more than enough to counteract any improvements Siemian has provided.

They Can’t Stop the Run

Denver still owns one of the best pass defenses in the NFL: They have an elite pair of pass rushers (Von Miller and DeMarcus Ware) and an elite pair of cornerbacks (Aqib Talib and Chris Harris Jr). Yet the Broncos run defense isn’t anywhere near last season’s level.

In 2015, the Broncos gave up 3.3 yards per carry (best in the league) and 83.6 rushing yards per game (third best). This year, it took them only 12 games to give up more total rushing yards than they allowed all of last season. They came into this week’s matchup with the Titans surrendering an average of 122.8 yards per game (28th) and 4.2 yards per rush (17th), and those numbers won’t improve after Denver gave up 180 yards on 42 rushes on Sunday. It was the sixth time this year an opponent reached 140 yards on the ground, something that happened just once last season.

Some of their struggles against the run have to do with the losses of defensive end Malik Jackson and linebacker Danny Trevathan in free agency, but it goes beyond the loss of two players. Denver simply hasn’t been able to line up and stymie its opponents’ run games like it could last year, and this has created a trickle-down effect for the potency of the entire unit. The Broncos were able to dictate terms to their opponents last season, first shutting down any semblance of a run game to force them into passing situations; then, when the Broncos knew opponents were going to pass, they could rush the quarterback with reckless abandon. It was a vicious cycle: get nowhere on the ground, be forced to pass, then get killed by the pass rush.

This year, teams that can run the ball have found much more success. Denver still has a potent pass rush, but opponents are now moving the chains and putting together longer drives because of their ability to get big plays on the ground. After giving up 81 first downs on the ground during all of last season, the Broncos have already surrendered 83 through 13 games.

The best antidote to an aggressive upfield pass rusher like Miller has always been, and continues to be, a good run game. Denver no longer has the ability to make its opponents one-dimensional, so it can’t unleash its dominant pass rush in the same way it did last year.

They Can’t … Run

While Siemian is a clear upgrade to the horror that Peyton Manning and Brock Osweiler provided at quarterback last year, Denver’s run game has completely fallen off a cliff. It was never a dominant group last season — the Broncos finished 14th in yards per carry (4.2) and 17th in yards per game (107.4), and scored 13 touchdowns in 2015 (tied for 12th) — but C.J. Anderson and Ronnie Hillman at least provided a means for moving the ball downfield as Manning and Osweiler nearly sabotaged the season by throwing pick after pick. This year, the run game has had the opposite effect, providing little to no support for the now-decent quarterback position. Against the Titans, the newly signed Justin Forsett coughed up a fumble on his first carry, yet he still got more totes than nominal starter Devontae Booker, who ran the ball three times to gain a whole yard. In all, the Broncos got just 18 yards out of nine carries.

With Anderson out for the year with a torn meniscus, the future doesn’t look too bright for the Denver run game. Part of the problem stems from the retooled Broncos offensive line — featuring disappointing free-agent acquisitions Russell Okung and Donald Stephenson at the tackle spots — failing to open any holes to run through, but neither Booker nor Forsett provides the type of “create my own yards even when the blocking isn’t there” ability that Anderson brings.

The lack of ground-game consistency has meant that Denver has put an awful lot on Siemian’s shoulders, and while he’s been an interesting story and an upgrade over last year’s quarterback debacle — he’s completed 61 percent of his passes at 7.3 yards per attempt, with 16 touchdowns and seven picks — no one’s going to confuse him with Drew Brees.

They Aren’t Winning As Many Close Games

The Broncos’ Super Bowl–winning campaign was a thrill ride from start to finish. Including the playoffs, they finished the season a ridiculous 11–3 in games decided by eight or fewer points. They executed well late in games, and in a few instances, they got lucky. This year, they’ve regressed to the mean in the “ball bounced their way” department. They lost to the Falcons by a touchdown after a failed onside kick with 19 seconds left. They lost to the Chargers by eight with another failed onside kick attempt with 27 seconds left. They lost to the Chiefs by three in overtime when head coach Gary Kubiak tried for a 62-yard field goal and failed. And they lost by three this week after Madden-generated tight end A.J. Derby fumbled the ball away with just over a minute left. On the season, Denver is 3–4 in games decided by one score.

Related The 10 Most Misguided Moves of the NFL Season

There’s no doubt that the Broncos deserved to win the Super Bowl last season; the way they dominated opposing quarterbacks was a thing of beauty. But they were also incredibly consistent in close games. This season, it’s been a different story. In a few cases, it’s been the result of key coaching decisions, and in others, it’s been a lack of execution on one side of the ball or the other. But with four out of Denver’s five losses this year coming in one-score games, the Broncos’ penchant for late-game magic hasn’t been nearly so dependable.

Despite all of that, the Broncos are in control of the sixth seed in the AFC, and we shouldn’t write them off just yet. Denver still has a very good defense — it came into this week first in Football Outsiders DVOA and did hold the Titans to just 13 points in a loss — but without Trevathan, Jackson, and a couple of role players like Antonio Smith, they don’t wield the same level of unrivaled talent across the board. Denver needs to shore up its run defense in order to fully exploit its still-dangerous pass rush, and it’s going to need a lot more from the run game if it wants to replicate the magic of its Super Bowl run last year. Since, as the now-familiar refrain goes, there are no dominant teams, the title is still there for the taking. But if the Broncos can’t fix these major problem areas, they’re going to be putting a lot of pressure on Siemian to carry them to wins, and they’re going to get a lot of games that look a lot like their loss in Tennessee on Sunday.