Following Monday night’s heart-wrenching loss to Kansas City, the Broncos find themselves 2-2 at the season’s first quarter pole. Now that we’ve got a quarter of the season under our belts, it’s time to look at a few Broncos storylines with an analytic lens and the help of Pro Football Focus.

Young players making large contributions

The surprisingly high level of snaps for youngsters, but more importantly their production, has been Denver’s biggest storyline throughout the first quarter of the season. Philip Lindsay and Royce Freeman have been such an impressive rookie tandem that they’ve all but supplanted former lead back Devontae Booker. The Broncos’ new rushing attack has even enjoyed success in obvious running situations, converting a first down or a touchdown on over a third of all attempts against an eight-man box. The duo has terrorized defenses, just as Bradley Chubb has been quietly terrorizing offensive lineman.

Chubb has just 1.5 sacks through four games, a little short of what was expected to enter the year. But despite not having the eye-popping numbers, Chubb has managed to be Denver’s most effective pass rusher. The rookie has won his matchup on an impressive 17.92 percent of snaps, good for 14th in the league, and has delivered pressure on 14.15 percent of snaps, good for 17th in the league. Both of which are better than Von Miller’s 12.40 percent win rate and 9.92 percent pressure rate. Chubb’s sack totals should begin to reflect this as the season goes on and he gets more experience.

The future certainly looks bright in Broncos Country.

Offensive lineman are offensive MVPs

Although the phenomenal rookie class has been instrumental in the offense’s improvement, the offensive line has been even more important. Since 2015, the Broncos offensive line has held the team back. Now, with the addition of Jared Veldheer and 2016 fifth-round pick Connor McGovern getting his first starts, the offensive line looks the best it has since the Mike Shanahan era.

PFF gave Denver a pass blocking efficiency rating of 87.4, good for 11th-best in the league. Center Matt Paradis leads the team in pass blocking efficiency with a 98.7, followed by guards Ronald Leary (98.0) and McGovern (97.7). If Garett Bolles can clean up his mental errors and continue to develop, Denver’s offensive line could soon become elite.

“No Fly Zone,” no more

As recent as two seasons ago, the Broncos boasted the best secondary in the league. With the departure of Aqib Talib and lack of an adequate replacement, the secondary has become more of a liability than a strength. Denver allowed Raiders quarterback Derek Carr to set an NFL record, as he became the first quarterback with at least 27 attempts to reach a 90-plus completion percentage.

Denver ranks 19th in yards allowed per reception (11.55) and 21st in opponent passer rating, allowing an average rating of 105.3. The Broncos secondary is among the worst when it comes to tackling as well, missing 18 through four games.

Most concerning though is that they rank 28th in the league in PFF’s forced incompletion metric. This means that Denver’s secondary is responsible for the incompletion on just 7.1 percent of attempts and the rest of the incompletions are due to an offensive error. If the Broncos want to sniff the playoffs they have to stop the receivers more often than 7.1 percent of the time.

This could be because of Denver’s opening schedule consisting of two of the best quarterbacks in the league, Russell Wilson and Derek Carr, and two of the hottest in Patrick Mahomes and Joe Flacco. But it won’t get any easier with Big Ben Roethlisberger, Jared Goff, and four divisional games remaining on the schedule.