Now, they head into an offseason of uncertainty and very likely change, a lot of it.
In a mistake-filled finale Sunday, the Denver lost to the Los Angeles Chargers 23-9 in what stood out as their worst performance.
From the four turnovers, to lackluster offensive play, to unfortunate penalties, the Broncos (6-10) just did not look like a team that was on its game.
After a midseason surge back into contention, Denver finished the year by losing its last four games. Broncos coach Vance Joseph fell to 11-21 in his two years with team and whether he returns for a third is an open question.
"Obviously, the first year, winning five and winning six this year, by the Broncos' standard, is not good enough," said Joseph, who's expected to meet Monday with Broncos general manager John Elway. "I totally get that, but I think we've put a lot of work in. It's a foundation that's been laid here that should pay off in the future. I think we have to honestly look at where we are and find a way to improve. ... We have a great staff, a locker room that cares and really good coaches. We have a bunch of good players. We'll see. It's not my decision, but I do want to be here."
Defensive lineman Domata Peko Sr. said he understands some roster changes are in the offing for the Broncos but he also feels the team can get better quickly with just some fine-tuning of the roster.
"I know that this offseason will be big for our team," he said. "And I know that Elway and (team president) Joe Ellis and the people upstairs will do a good job of gathering up more players to help us out, because I feel like we're really close. We just need some help."
The Broncos were not without some fight in their last regular-season game but their failure to move the ball offensively early on, after their defense had forced early Chargers turnovers, was reminiscent of the struggles they've had in establishing a consistent attack for most of the year.
"It was just one of those games where it was a slugfest," wide receiver Courtland Sutton said. "They couldn't move the ball either. When it was 7-3, their offense didn't score that. Their defense did. They weren't scoring points really. The times they were scoring, we were putting them in position to score so they had a short field.
"I would say both offenses didn't have a tremendous day today. It's hard to say what the reason was. We just didn't connect like we were supposed to."
Denver's offense also was hurt by season-ending injuries to some of their best play-makers, including wide receiver Emmanuel Sanders and running back Phillip Lindsay, though quarterback Case Keenum refused to lay blame for the offensive problems on the loss of key players.
"There's no excuses for me," Keenum said. "I hold myself to a high standard. It's not for me to judge whether to say it's fair or not."
Each team had four turnovers but the Chargers made more out of them.
The Chargers capitalized on Denver's second turnover to move in front 14-3 on Philip Rivers' 3-yard touchdown pass to Mike Williams with 3:46 remaining in the third quarter. Rivers only had to drive the Chargers 16 yards for the score after Broncos wideout Tim Patrick fumbled following a completed pass.
Denver managed to answer with Keenum's 20-yard touchdown pass to fullback Andy Janovich with 10:10 remaining in the fourth quarter. But that too ended badly for the Broncos when Keenum's conversion pass attempt was intercepted by cornerback Casey Hayward Jr. and returned 101 yards down the right sideline for two points for the Chargers.
The Chargers sealed the game by mounting a 75-yard drive that Austin Eckler finished off with a 1-yard touchdown run with 5:48 left to play.
The Broncos trailed 7-3 at halftime after a mistake-filled 30 minutes of play.
Consider their initial score -- a 28-yard field goal by Brandon McManus with 11 seconds left in the second quarter.
Just a couple minutes before, the Broncos were facing a 3rd-and-goal at the 6-yard line. Keenum threw a pass into the end zone that deflected off the chest of tight end Matt LaCosse and into the hands of safety Jahleel Addae. He returned it to the 16, where he attempted to lateral to a teammate who wasn't expecting it and guard Elijah Wilkinson fell on the loose ball to give the Broncos a fresh set of downs at the Chargers' 20-yard line.
Denver managed to advance the ball to the 6 again before linebacker Joey Bossa's third-down sack of Keenum led to the McManus field goal.
The Chargers scored earlier in the second quarter on linebacker Kyle Emanuel's 18-yard touchdown return, scooping up Keenum's backward pass, which had rolled away from the grasp of Royce Freeman.
The turnover was preceded by two holding calls on left tackle Garett Bolles, including the first infraction, which resulted in the nullification of a 54-yard touchdown run by Devontae Booker.
Denver's defense also set up the Broncos' offense with a pair of first-quarter interceptions of Rivers -- one by cornerback Isaac Yiadom and the other by safety Will Parks -- but both possessions ended in punts by the Broncos.
NOTES: Broncos RB Royce Freeman, with 65 yards (37 rushing and 28 receiving), surpassed 500 yards from scrimmage this season. Denver became just the third NFL team with three different rookies with at least 500 yards from scrimmage in a season. Rookie RB Phillip Lindsay had 1,287 yards before suffering a wrist injury a week ago and rookie WR Courtland Sutton had 678 yards receiving going into the final game of the season.