After the Broncos started this season 4–0, I wrote a tribute to John Elway, lauding him for his tendency to buck conventional wisdom and outside assumptions about how he should construct his roster.

Elway confounded observers when he let Brock Osweiler sign with Houston and inked punch-line veteran Mark Sanchez as Osweiler’s ostensible replacement. Elway then further flummoxed everyone when he cut Sanchez and installed the unproven Trevor Siemian and Paxton Lynch as the Broncos’ quarterbacks.

The thinking as the 2016 season dawned was that the team’s defense and running game would be enough to get back to the playoffs as long as the QB play was competent. The defense has mostly held up its end, ranking among the statistical leaders once again, though the unit has lacked some of that intangible ferocity and historical dominance that the team rode to the promised land last year.

Siemian hasn’t been terrible. He ranks among the top two-thirds of NFL starters in QBR and QB rating, two byzantine formulas that measure a signal-caller’s true effectiveness. (Lynch was adequate during his few cameos but clearly needs more seasoning before Gary Kubiak hands him the keys for good.) Meanwhile, Osweiler appears to have lost his starting job in Houston after throwing two more interceptions on Sunday and watching his backup lead the Texans to a comeback win, leaving some to wonder if the contract Denver wouldn’t agree to sign him to will prove to be the worst in league history. So on that front, there’s no doubt Elway made the right call (though he did draft Osweiler in the first place).

But where the Broncos have truly fallen short is in the running game, which has been beset by injuries and is among the least productive in football. Kubiak loves to use the run to set up the pass, and Siemian either isn’t experienced or talented enough to carry a team when the runners aren’t.

This all came to a head after Sunday’s 16–3 loss to New England, when a shouting match between the subpar offense and the overburdened D reportedly erupted in the locker room. If you hold Tom Brady to 16 points and fewer than 200 yards passing at home, you should expect to win, yet this one was never particularly close because of the offense’s inability to get anything going.

The Broncos finish up with games against Kansas City and Oakland, both having dominant years. Even if the Broncos manage to win both games they’ll still need help to make the playoffs–all of which means it might be time to start planning for 2017.

Job number one for Elway and company should be to instill more firepower into the team’s attack. Although the defense almost literally carried the Broncos to a title last year, the adage “defense wins championships” has long been a myth. The truth is, depth, potent balance on all sides of the ball, and a little luck usually wins champioships, and with the AFC West now looking like it will be among the toughest divisions in football for the next few years, the Broncos and Elway will need to make major adjustments if they want to resummit the mountaintop.

Follow 5280 editor-at-large Luc Hatlestad on Twitter at @LucHatlestad.