ENGLEWOOD • It’s only the fourth game of the season. So, yes, it’s early.

But Monday’s clash with the entertaining and dangerous Kansas City Chiefs carries the feel of a momentous game, no matter the date on the calendar. The Chiefs have beaten the Broncos five straight times, including three straight at Mile High. The Chiefs boast the game’s most dazzling young talent in quarterback Patrick Mahomes.

Here’s what worries me: The Chiefs could devour the Broncos on national TV and send us into yet another fall spent wishing a different team played on the edge of downtown Denver.

Coach Vance Joseph stood outside the sunshine on Wednesday afternoon and marveled at the strength of the Chiefs. His was not the voice of strident optimism.

“They’re explosive,” he said. “Right now, they’re averaging 400 yards a game, almost 40 points a game. The quarterback is playing at a high level. He’s got multiple weapons. … It’s going to be difficult for us to get them stopped, but we’re looking forward to the challenge.”

Woody Paige: Patrick Mahomes and Kansas City Chiefs bring lots of offense to Denver matchup

Oddsmakers appear to have listened to Joseph’s assessment. The visiting Chiefs are five-point favorites.

“I’m not surprised,” Joseph said. “I’m not surprised that they are the favorites. That means nothing.”

Well, it means something. The extraordinarily happy times of the Peyton Manning era (2013-2016) hide the bitter times more often found in the last dozen years. During the Peyton years, visiting teams didn’t march into Mile High as heavy favorites.

In the eight seasons when Peyton was not leading the offense, the Broncos finished 51-64 and it usually was a solid idea to bet on the visitors.

We’re still discovering if Case Keenum follows a recent, depressing norm. Kyle Orton, Tim Tebow and Trevor Siemian were backup quarterbacks forced to start because Broncos leaders paid to find NFL-starter-caliber talent failed to find NFL-starter-caliber talent. (Paxton Lynch is, it turns out, not even a worthy backup.)

I applauded John Elway’s decision to sign Keenum in the offseason. He had delivered a superlative season for the Vikings, throwing 22 touchdowns and only seven interceptions while performing a strong, season-long imitation of great Drew Brees.

But there were questions hovering over Keenum: Was he a one-season wonder? Was the quarterback nobody wanted in July 2017 worth $20 million in March 2018?

Let’s just say Keenum has left those questions hovering. He’s been consistently erratic. His late interception doomed all hope at Baltimore on Sunday, and the Broncos won despite him in the opener against Seattle.

Another bumbling Keenum game will inspire loud and rude booing from fans at Mile High. Trust me on that one. And, more important, another bumbling game will inspire Keenum’s Bronco teammates to wonder if he’s an NFL-quality starter.

Last season, Joseph often looked helpless and overwhelmed. The Broncos were sinking, on their way to a 5-11 record, and the rookie coach just sort of stood around and watched.

He’s become an aggressive activist in his second year. On Sunday in the Baltimore rain, punter Marquette King struggled mightily. He averaged only 39.7 net yards on seven kicks and never remotely resembled a punter worthy of a $2 million annual paycheck.

Joseph knew Tyreek Hill would be catching Bronco punts Monday. Hill, mega-scary, has sprinted to four touchdowns on only 68 career returns. Joseph moved decisively, and wisely, signing free agent punter Colby Wadman to either take King’s job or awaken the slumbering punter.

“It’s a performance-based business, so we’re trying to get better there,” Joseph said.

It is a performance-based business, coach. Be sure to keep that in mind.