All this despite a pass defense that was among the NFL's worst.
As the Chargers try to build on that surprising success this year, the team already took one big step to remedy the situation in May's NFL draft by selecting TCU cornerback Jason Verrett in the first round.
However, it's San Diego's latest move in the secondary that's going to have the biggest impact, one that could go well beyond just Southern California.
According to Mike Garafalo of Fox Sports.com, the deal is for a single season:
Despite making the Pro Bowl for the first time in 2013, Flowers fell out of favor with the Chiefs last year. The 28-year-old struggled both in the press-man scheme employed by defensive coordinator Bob Sutton and playing the slot, dropping all the way to 87th among cornerbacks in Pro Football Focus' (subscription required) rankings.
Flowers' struggles last year aside, this is still a 450-foot moon shot of a home run signing by the Bolts.
For starters, while Flowers may have struggled last year, PFF recently pointed out that his play prior to 2013 had been substantially better:
Also, when I wrote that the San Diego pass defense was among the worst in the NFL last year, I wasn't kidding.
The Chargers ranked 29th in the NFL in yardage allowed through the air, surrendering just under 260 yards a game. Pro Football Focus was even less kind, ranking the Chiefs 30th in pass coverage in 2013.
Football Outsiders took things one step further, ranking the Chargers as the NFL's worst pass defense overall.
Here's all you really need to know: Flowers' awful, 87th-place season last year would have ranked him first among Chargers cornerbacks at PFF.
It isn't just that Flowers instantly becomes the team's best cornerback, either.
Back before May's draft, Dane Brugler of CBS Sports wrote of Verrett, "His lack of size likely limits his NFL ceiling, but he has the easy change of direction skills, light feet and physical and mental toughness to shine in the NFL, ideally suited as an inside nickel corner."
It's that last part where Flowers will come in handy. Flowers' arrival takes a huge weight off Verrett's shoulders. There's no longer a pressing need for Verrett to start outside, which will allow the Chargers to not only ease him in a bit but also kick the rookie inside where he belongs.
With Verrett's acclimation to the NFL already slowed by shoulder surgery, that's a veritable symphony of music to the Chargers' ears.
Never mind that at 5'9" (the same as Verrett), Flowers can teach Verrett a thing or two about how to play bigger than your height in the program.
Frankly, the whole thing couldn't have worked out better for San Diego. Had Flowers been a free agent back in March, the Chargers probably wouldn't have been able to afford him.
In essence, by waiting as long as they did to release Flowers, the Chiefs did their AFC West rivals a huge favor.
It's a favor they may well live to regret. The Broncos may remain the class of the division, but one of the teams jockeying for second (and a wild-card spot) just patched its biggest hole on defense with a Pro Bowler.
At the expense of the other.
Gary Davenport is an NFL Analyst at Bleacher Report and a member of the Fantasy Sports Writers Association and the Pro Football Writers of America. You can follow Gary on Twitter: @IDPManor.