You could say the madness really began in December 2014, against the Chargers, no less. It was the third-to-last game for the Broncos and it was a victory.

But it was also the start of Peyton Manning’s string of injuries that has clearly affected his play — especially after his record-setting 2013 season. Manning hurt his quad in that game, an injury that would be shielded long enough for outsiders to question his talent, his arm strength and his ability to play football at age 38.

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But to keep this clean and simple, I’m starting in last January. Calendar year. In last January, the Broncos fell to Manning’s former team and his replacement in the divisional playoffs, a defeat that left general manager John Elway in dismay because his team did not go out “kicking and screaming.”

So that was the start. That was the start of what may be one of the wildest seasons for the Broncos (I’m hesitant it to put in on a Tim Tebow level of craziness).

Think of all that has been crammed into the last 12 months: an early playoff exit, a coaching overhaul, the incredible defense, the un-Manning-like offense, the supposed fall of an icon, the injuries, the rise of a franchise’s potential future star, the allegations, the return of an icon — I KNOW!

For kicks, let’s relive it all (we have two weeks before the postseason, so we might as well):

Jan. 11: The Broncos lose to Colts, 24-13, at home in a divisional playoff game. Everyone’s mad. Elway especially. It also leaves Manning’s future uncertain. After the game, he’s noncommittal about returning, despite saying nearly three weeks earlier that he would like to return “if the Broncos will have me.”

Jan. 12: Broncos part ways with John Fox in the wake of the early playoff exit. Fox led the Broncos to four consecutive AFC West titles.

Jan. 18: Gary Kubiak, John Elway’s former backup and offensive coordinator, is hired as head coach.

Jan. 28: Wade Phillips, a former Broncos defensive coordinator and a coach who had been out of football for the past year, is brought back as DC. Phillips, however, was not the Broncos’ first option for the job. They wanted Vance Joseph, but the Bengals refused to release him from his contract. So they got Phillips, who installed his version of the 3-4 and turned the Broncos’ good defense into the best of 2015 in multiple categories, and one of the franchise’s finest in history.

March 4: Manning says he will return and accepts a $4 million pay cut.

April 30: The Broncos move up five spots in the draft to take Shane Ray at No. 23, given them potentially four elite edge rushers, with Von Miller, DeMarcus Ware and budding star Shaquil Barrett.

May 29: Dealing an early blow the Broncos’ season, veteran tackle Ryan Clady is placed on season-ending injured reserve after tearing his ACL.

July 15: Minutes before the deadline, the Broncos reached a five-year, $70 million contract with star receiver Demaryius Thomas. But he missed the team’s offseason program because of the lengthy negotiations.

Sept. 13: Aqib Talib’s pick-six in the Broncos’ opener against the Ravens, Kubiak’s former team, sets the tone for the defense. But it also raises questions about the offense, which was supposed to marry Manning’s strengths with Kubiak’s run-focused system.

Nov. 1: In the Broncos’ most complete game at the time, Manning & Co. hand the Packers their first loss of the season on a night dedicated to Pat Bowlen. The victory — for a while, anyway — quiets concerns about Manning’s fit in the offense and the team’s potential going forth, because on this night, everything is clicking.

Nov. 2: First Clady. Now Ty Sambrailo. The Broncos’ second-round draft pick and starting left tackle is placed on IR with a shoulder injury. Along with Jeff Heuerman, two of the Broncos’ top three picks are on IR.

Nov. 3: The Joe Thomas deal that seems promising and oh-so-close fizzles as the trading deadline passes. The injured O-line that has already undergone multiple shifts stays as is.

Nov. 15: Manning, who had thrown at least one interception in each of his previous eight games, saves the most for the Chiefs, in Denver. After breaking Brett Favre’s all-time passing yards record in the first quarter, Manning threw three more picks for a total of four in two-and-a-half quarters. He was benched midway through the third and finished with the worst possible passer rating: 0.0.

Nov. 16: Manning’s foot injury — the one he aggravated on the turf at Lucas Oil Stadium earlier in November — prompts Kubiak to name Brock Osweiler the starter while Manning rehabs.

Nov. 22: In his first NFL start, on his 25th birthday no less, Osweiler leads the Broncos to a touchdown in their first possession and then to a 17-15 win over their former coaches in Chicago. The Broncos’ run game produces a then-season-high 170 yards with Osweiler at the helm, and he finishes 20-of-27 for 250 yards and a pair of touchdowns.

Nov. 29: The Broncos beat the Patriots. In overtime. On a touchdown run by C.J. Anderson that will go down in Broncos lore. Uh … Manning who?

Dec. 26: As a subplot to the season, an al-Jazeera report claims to link Manning and his wife to human growth hormone. As details about the report and its sourcing continue to unfold, skepticism and additional questions are raised.

Jan. 3, 2016: Manning is active for the first time since the Kansas City loss and returns in the third quarter after the Broncos commit five turnovers. Manning engineers three consecutive scoring drives en route to a 27-20 win. Manning plays savior, but the team’s QB situation is even more unclear …

Jan. 4, 2016: Kubiak isn’t ready to name his starting quarterback for the Broncos’ divisional playoff game Jan. 17.

May the drama continue …

CHEW ON THIS

• According to MyTopSportsBooks, the Broncos have the fourth-best odds (8/1) to win Super Bowl 50, behind the Cardinals (5/1), Patriots (6/1) and Panthers (6/1).

• Pete Maravich, one of my favorite basketball players ever, died at age 40 on this day in 1988. Very sad. So let’s enjoy this together.

• Why Brock Osweiler should start at QB with Peyton Manning in relief, columnist Mark Kiszla writes.

• Jarome Iginla became just the 19th player in NHL history to notch 600 goals Monday in the Avs’ win over the Kings.

• Broncos cornerback Chris Harris believes his bruised shoulder will be “ready to go” for the playoffs.

WATCH THIS

This psych-rock band covered a country ballad without ever hearing the original song.

HAPPY BIRTHDAY

Basketball Hall of Famer Alex English turns 62. The former Nuggets legend spent 11 seasons in Denver, where he is the franchise’s all-time leading scorer with 21,645 points.

Nicki Jhabvala: njhabvala@denverpost.com or @NickiJhabvala

Online sports producer Joe Nguyen contributed to this story.