ENGLEWOOD – This Broncos’ season began with hopes pinned on Keenum and the Kids.

Meaning no disrespect to Case Keenum -- whose grit, unyielding confidence and steady quarterback play has helped lead the Broncos through their resurgence.

But against the San Francisco 49ers on Sunday, the Broncos will start six rookies – three on offense (receivers Courtland Sutton and DaeSean Hamilton and running back Phillip Lindsay) and three on defense (outside linebacker Bradley Chubb, inside linebacker Josey Jewell and cornerback Isaac Yiadom).

And punter Colby Wadman is also a rookie, as are No. 2 running back Royce Freeman and core special teamer Keishawn Bierria.

Where would the Broncos be without the John Elway/Matt Russell rookie class of 2018? Lou Saban’s 1967 Broncos had 24 rookies on their roster and 10 were full-time starters.

But that team was also a miserable, 3-11. The current Broncos are 6-6 and streaking thanks to their kids. Vance Joseph has been an NFL coach for 14 years and he’s never been part of a team that relied so heavily on rookies.

“I have not, but again, that’s where we are,’’ Joseph said. “We’re in Week (14), so these guys are experienced. This class is very mature. To have Courtland and DaeSean starting for us on Sunday, and Josey and Yiadom, ‘Chubby’, all those guys, it’s exciting to have so many young guys play at a high level. No worries.”

The Broncos have overcome two other major obstacles – strength of schedule and injuries -- to remain a game out of an AFC playoff spot with four games remaining.

Entering week 14, the Broncos have played the NFL’s toughest schedule as their opponents have a combined .580 winning percentage.

That’s what happens when you play the 10-2 Kansas City Chiefs’ twice, the 11-1 Los Angeles Rams, the 9-3 Houston Texans and 9-3 Los Angeles Chargers, the 7-4-1 Pittsburgh Steelers and 7-5 Baltimore Ravens.

NFL schedule strength (through 12 games)

Rank … Team … Opp. W-L-T … PCT

1. Broncos ……..… 83-60-1 … .580

2. Raiders ………… 80-63-1 … .559

3t. Bengals ……… 78-64-2 … .549

3t. Browns ……… 78-64-2 … .549

5. Titans ………… 78-65-0 … .545

The schedule gets considerably easier down the stretch, at least on paper, as the Broncos play 2-10 San Francisco, 4-7-1 Browns and 2-10 Raiders in their next three games before finishing with a home game against the Chargers.

But as the Broncos take on these weaker teams, how strong is their own roster? The Broncos rank No. 6 in the league with 104 missed games because of injury.

And that doesn’t include the recent devastating injuries to No. 1 cornerback Chris Harris Jr. and No.1 receiver Emmanuel Sanders who suffered injuries within the past six days that will cause them to miss the final four regular-season games.

Rank … Team ………. Games missed w/injury

1. Ravens ………….. 121

2. Eagles ……………. 120

3. Washington …… 119

4. Cowboys ……….. 115

5. Patriots …………. 110

6. Broncos …………. 104

Perhaps, it’s time to give Joseph some credit for holding this team together. Or compliment Elway, the general manager, and his top assistant Russell for putting together a roster with depth. Young depth at that.

Mostly, credit the Broncos’ rookie class of 2018.

“When they’re good players, it works,’’ Joseph said. “When they’re not good players, it doesn’t work. For us, it’s been a special class. To watch these guys grow and play for us—even in Weeks 4, 5, 6, 7 and 8, for us to win football games, that class had to play well.