CLEVELAND -- In seven weeks the best-laid plans of the Denver Broncos have unraveled like a sweater on the sale rack.

The Broncos' offense once again got revved up far too late to make a difference and their defense had another night of missed tackles, assignment issues and bad luck in a 17-14 loss to the Cleveland Browns. It was their fourth consecutive loss after a 3-0 start, as their undefeated September has given way to a winless October.

"Very disappointing, you look at the final score and see 17-14 and you're going to think 17 points is good enough defensively," said Broncos coach Vic Fangio. "But we didn't play good defensively [Thursday]. We let them drive it too much, way too many third-and-1s and we didn't play well enough to win the game."

And while the Broncos will pack plenty of woes in their luggage for the trip home to an increasingly impatient fan base, it is the team's defense that felt the sting most Thursday. As training camp drew to a close the Broncos had visions of a Bradley Chubb-Von Miller-driven pass rush, backed by the league's highest-priced secondary and defensive linemen such as Dre'Mont Jones and Shelby Harris set to flourish with all of the attention going away from them.

Chubb had ankle surgery last month. The Broncos have seen both of their starting inside linebackers -- Alexander Johnson (chest) and Josey Jewell (chest) -- go on injured reserve and Miller left Thursday night’s game before halftime because of a left ankle injury.

The bottom line is the Broncos have had enough problems over the past five-plus seasons since their last playoff game -- Super Bowl 50 -- but the fortunes of the coveted Miller-Chubb combo over the past four years offer a window into much of the frustration.

Chubb missed all but four games of the 2019 season with right ankle surgery. Miller missed 2020 and Chubb went to injured reserve in Week 3 due to left ankle surgery. Miller's injury -- he will be examined again in Denver on Friday after team sources said Thursday the initial X-rays at the stadium showed no fracture -- is now on the list of defensive troubles the Broncos didn't expect.

The secondary, which added Ronald Darby and Kyle Fuller in free agency to go with first-round draft pick Pat Surtain II, has had too many moments when veterans who believed their experience would create instant chemistry haven't looked on the same page. Surtain has been one of the league's best rookies, but Fuller has essentially been benched and Darby missed four games because of a hamstring injury.

And Denver has given up big plays with far more frequency than any playoff hopeful -- which is what the Broncos said they were last month -- can get away with. Whether it's been Trevor Lawrence uncorking a touchdown throw, or Ben Roethlisberger, Lamar Jackson, Derek Carr or now Case Keenum, the Broncos defenders simply haven't held the line early. And the Broncos' offense isn't equipped to play from behind, let alone from the opening minutes of a game.

Thursday night, the Browns became the fourth team this season, and third in a row, to score on its opening drive against Denver. Cleveland went 75 yards in five plays and just kept on going.

By halftime the Browns had held the ball for 21 minutes, 11 seconds, accounting for 38 plays and a 10-0 lead. And when the Broncos showed a little offensive spark with a touchdown to open the second half, the Broncos' defense once again couldn't hold the line. The Browns drove 75 yards in 13 plays for a 17-7 lead as the third quarter drew to a close -- a rinse-and-repeat scenario that played out again when the Broncos closed to 17-14 late in the fourth quarter.

Quarterback Teddy Bridgewater, who battled through a foot injury that had him limited even in walk-throughs this week, once again spurred some fight down the stretch, but another early deficit was again too much hill for these Broncos to climb.

And perhaps most troubling, beyond the prospect of Miller's injury causing him to miss significant time, is the Browns consistently pounded out yardage in the run game -- 119 yards rushing by the end of the third quarter without their two best running backs, Nick Chubb and Kareem Hunt, in uniform.

D'Ernest Johnson, Cleveland's third-string running back, pounded away at the Broncos' defense after Denver had cut the Browns' lead to 17-14 with just over five minutes left, helping the Browns run the clock out. He ended up with a career-best 146 yards rushing and a touchdown.

Vic Fangio was hired by John Elway in 2019 to take a defense the Broncos believed was still playoff-worthy and make it into a turnover-snatching, sack-producing foundation for a postseason return. Instead, the defense has been annually eroded by injuries to one starter after another and the offense consistently scores 21 or fewer points.

And 10 games still await with no help on the way.