Is 2018 the last chance for this Broncos core?

Obvious parallels for the Broncos' 2018 blueprint don't exist. Two come to mind, the closest possibly being a past Denver team. But even that’s a slight reach.

The Broncos were five seasons removed from their second Super Bowl championship upon signing Jake Plummer in 2003. Their current version’s stakes are much higher.

This team’s best assets remain the holdovers from Super Bowl 50. The past two years did not produce a Peyton Manning successor. John Elway’s penchant for tall, raw quarterbacks created mismatched timelines — signal-callers holding back a championship-caliber defense — and induced a desperate attempt to pry a contention window back open.

If the Broncos can’t turn their operation around this year, they’re staring at a reluctant rebuild. 

Case Keenum now holds the keys to the primes of Denver’s championship core, and the Broncos' playoff aspirations depend on a journeyman who either has experienced a late emergence as a viable starter or is on the heels of a circumstances-driven outlier.

The answer to that question will determine the course of this franchise for the foreseeable future.

Timeline 1 would give Denver's defense a chance to matter again, inserting a surprise contender into a weak AFC field. Timeline 2? The kind of overhaul Elway’s seeking an excuse to avoid.

They aren’t generating much buzz, but the Broncos are one of the NFL’s more fascinating teams. Everything from a Keenum-was-fraudulent/”Elway should’ve hired Kyle Shanahan” reality to a Rich Gannon 2.0 helps Von Miller and Co. wear orange in January again is in play.

This situation is without clear precedent, but the ’03 Broncos and '06 Ravens are in the ballpark. The former's trajectory represents maybe the best-case scenario.

Mike Shanahan ditched Brian Griese for Plummer, and the then-29-year-old free agent pickup led the Broncos to three straight playoff berths. The ’03 team still had Super Bowl XXXIII starters Shannon Sharpe, Rod Smith, Tom Nalen and Trevor Pryce, along with a few other late-1990s mainstays. The Broncos' early-2000s iterations were fairly forgettable; Plummer helped them jump a level in the mid-aughts. They topped out at 13-3 in 2005 and became the first team to beat the Bill Belichick/Tom Brady Patriots in the playoffs. 

A comparable run from the 30-year-old Keenum would complement the Denver defense after a wasted 2017. The Plummer-era Broncos featured a much better coach and rushing attack; this one has more players left over from a victory parade.

In the case of Baltimore, seeing 2003 first-rounder Kyle Boller fail to develop, the Ravens signed Steve McNair in 2006. Baltimore went 13-3 that season, but McNair injuries a year later derailed that QB plan.

Super Bowl winners have rarely needed free agent quarterback aftermaths. Only one team since free agency’s inception (the 2001 Ravens, who replaced Trent Dilfer with Elvis Grbac) signed a starting quarterback less than four years after winning a title. (The Buccaneers added Griese in 2004, but he began his tenure backing up Brad Johnson.)

Having seen both of their championship quarterbacks retire on top, the Broncos have encountered historically unique predicaments. Each time, they tried the traditional draft-the-heir-apparent route. But 17 years after Griese succeeded Elway and started for four seasons, even making a Pro Bowl, the modern plan's bombed. Paxton Lynch’s time in Denver looks to be ending after less of a look than Brock Osweiler received, and that will double as a strange conclusion.

Only one first-round quarterback drafted from 1991-2016 received fewer starts than Lynch's four with his original team — Jim Druckenmiller, a 1997 49ers first-rounder who made one career start. Johnny Manziel made eight. Ryan Leaf got 18 in San Diego. Jamarcus Russell had three seasons to prove he was ill-equipped.

The Broncos’ refusal to rebuild didn’t leave time for a young passer to fail in games. Mere offseason and preseason shortcomings did in Lynch. If Denver featured a younger roster, Lynch or Chad Kelly probably starts this season with Keenum playing elsewhere. 

Denver's 2016 decision to trade up for Lynch essentially prevented an investment in one of this year’s higher-regarded prospects. Bypassing Josh Rosen or Josh Allen for Keenum could turn out to burn the Broncos if one of the Joshes turns into a franchise guy.

McNair and Plummer enjoyed track records as established starters. Keenum's made double-digit starts in a season once. His 78.2 career passer rating entering 2017 was 20 points below the mark he posted for the Vikings. 

Placing a team’s future in the hands of a 6-foot-1 nomad — albeit one who thrived on a per-play (first in 2017 QB DVOA) and overall (fourth in DYAR) basis — is an obvious risk. But free agent prize/object of Broncodefenders' affection Kirk Cousins appeared fixated on Minnesota. Unless Elway wanted to turn his seasoned roster over to a rookie and a lower-ceiling bridge vet, this was his best hope at a potential plug-and-play, long-term solution.

Keenum is perhaps significantly better than every other post-Manning option. Even going from horrendous to average at sports' marquee position would make these Broncos a factor.

Elway staked his reputation on Keenum, because if this fails, the Hall of Famer's general manager career will be scrutinized. If Keenum joins Osweiler and Lynch in the eighth-year decision-maker’s “miss” column, Elway’s success — the Broncos' radical transformation from an offensive superpower in Super Bowl XLVIII to defensive force by Super Bowl 50 notwithstanding — will be viewed on the surface as largely Manning-enabled.

If this rare strategy works, however, Elway will re-establish himself as one of the league's best GMs.

This will almost certainly be the final year Denver’s best offensive players — Demaryius Thomas ($17.5 million 2019 cap number) and Emmanuel Sanders (due $13M next year) — will be on the same team. And the Broncos’ top defenders — Miller and Chris Harris — each turn 30 next year.

It’s debatable that the Broncos should’ve joined the Seahawks in blowing up their roster earlier than expected. But Russell Wilson can expedite a rebuild. The Broncos have no such cheat code. Their defense is their window. 

Denver's rookies have received early praise, but no real core beyond the Super Bowl cogs exists, amplifying the pressure on Keenum to restore that group's relevancy. 

Keenum can reignite the Broncos and etch his name among the NFL's many unlikely success stories. His falling back to earth will allow many to deem this era of Broncos football a Manning creation, dismissing the supporting cast as players who couldn’t sustain success without the legendary passer. 

That’s a rather significant responsibility bestowed on a first-year Bronco, and it's one of 2018's best NFL subplots.