If you ask a casual fan when Patrick Mahomes took over the Kansas City Chiefs, they’ll probably point to 2018. That’s the year he threw for 50 touchdowns, won the MVP, and basically broke the NFL’s spatial geometry. But that’s not actually when it began.
The real story starts in a draft room in 2017, involves a massive gamble by Andy Reid, and features a freezing cold New Year’s Eve game in Denver that almost nobody remembers.
Honestly, the timeline is a bit weirder than people think. You’ve got this weird bridge year where he was technically a Chief but essentially a ghost on the sidelines. Let's look at the actual dates and the "sliding doors" moments that turned the franchise into a dynasty.
The Day the Chiefs Remade Their Future
It was April 27, 2017. The Chiefs didn't just pick Mahomes; they hunted him. Kansas City originally held the 27th pick in the first round. That’s late. Usually, you don't get a generational quarterback at 27.
General Manager Brett Veach and Head Coach Andy Reid saw something in the Texas Tech kid that others missed. Or rather, they saw the "Air Raid" system flaws as coachable traits. They traded their 27th pick, a third-round pick, and their 2018 first-rounder to the Buffalo Bills just to jump up to the 10th spot.
When did Mahomes start with the Chiefs? Officially, his contract was signed on July 20, 2017. It was a four-year, $16.42 million deal. At the time, he was the backup. He was the "apprentice." Alex Smith was still the guy, and Smith was actually having a career year.
The Redshirt Season
Most people forget that Mahomes spent 16 out of 17 weeks in 2017 holding a clipboard. It’s a concept that feels ancient now. Today, top-10 picks usually start by Week 3. Reid stayed patient.
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Mahomes spent that year learning how to read NFL defenses from the scout team. He would famously try "no-look" passes against the Chiefs' starting defense in practice, driving the coaches crazy and making the veterans realize this kid was different.
The December Debut: Denver 2017
The actual on-field start happened on December 31, 2017. Week 17. The Chiefs had already locked up the AFC West and the fourth seed in the playoffs. They had nothing to gain by playing Alex Smith.
So, they threw the rookie into the fire.
It was a meaningless game on paper but a massive scouting report for the world. Mahomes walked into Mile High Stadium and looked... well, like Mahomes. He didn't throw a touchdown. In fact, he threw an interception. But he completed 22 of 35 passes for 284 yards.
"He made Albert Wilson look like a Pro Bowler that day." — Every Chiefs fan who watched that game.
Wilson caught 10 passes for 147 yards. Mahomes was rifling balls into windows that Alex Smith wouldn't even look at. He led a 67-yard scoring drive in the final minutes to set up a Harrison Butker field goal. Chiefs won 27-24.
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That was the "Aha!" moment. The front office knew right then that the Alex Smith era was over.
Becoming "The Guy" in 2018
The permanent transition happened on January 30, 2018. That’s when the Chiefs agreed to trade Alex Smith to the Washington Redskins. It was a bold move. Smith had just led the league in passer rating.
But the Mahomes era had officially arrived.
His first start as the permanent QB1 was September 9, 2018, against the Los Angeles Chargers. He didn't just play well; he exploded.
- 256 passing yards.
- 4 touchdowns.
- Zero interceptions.
- A 127.5 passer rating.
The next week against the Steelers? Six touchdowns. By Week 2 of his first full season, he had already broken the NFL record for most touchdown passes in a season’s first two weeks.
Why the "Wait and See" Method Worked
There is a lot of debate in the sports world about whether Mahomes would have been this good if he had started Week 1 in 2017. Honestly, probably not.
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By sitting behind Alex Smith, he learned the "boring" parts of being a quarterback. He learned how to study film. He learned how to manage a huddle. When he finally took the field, he had the raw physical tools of a 22-year-old with the mental prep of a veteran.
Key Milestones in the Mahomes Timeline
- Drafted: April 27, 2017 (10th Overall).
- First Career Start: December 31, 2017 (vs. Denver Broncos).
- Named Full-Time Starter: January 30, 2018 (Post-Alex Smith trade).
- First Home Start: September 23, 2018 (vs. San Francisco 49ers).
- First MVP Award: February 2, 2019.
The Legacy of the 2017 Choice
The Bills, who traded the pick to the Chiefs, eventually got Josh Allen, so they aren't crying. But the rest of the league? They're still reeling.
Mahomes didn't just "start" with the Chiefs; he reinvented them. Before he arrived, the Chiefs were a solid, respectable team that usually lost in the first round of the playoffs. Since he took over in 2018, they haven't known anything other than AFC Championship games and Super Bowl Sundays.
If you're looking for the exact second the league changed, it wasn't a touchdown pass. It was a cold afternoon in Denver where a rookie in a red jersey proved he was ready for the big lights.
Actionable Insights for Fans and Analysts
If you're trying to track the development of "the next Mahomes," don't just look at the stats. Look at the situation. The Chiefs provided a perfect ecosystem: a Hall of Fame-level play-caller in Andy Reid, a veteran mentor in Alex Smith, and the patience to let a young player sit for a year.
For those looking to deep-dive into the "Mahomes Effect," start by re-watching the Week 17 game from 2017. You'll see the raw footwork and the risky throws that would eventually become his trademark. It’s the blueprint for how to transition from a promising prospect to a league-altering superstar.