This key to the Chiefs' turnaround is something they haven't done in four years

The blitz call came to linebacker Nick Bolton in the first quarter of a Week 4 game last fall, with the Chiefs trailing by a touchdown and the Ravens marching toward expanding the lead.

The blitz, Bolton expected.

The exact blitz? He’d never called it.

That was the backdrop for a game-changing interception early last season - a blitz that a quarterback hadn’t seen on film because the defense had never put it on film.

Which, in essence, perfectly sums up the complexity of a Steve Spagnuolo defense.

Or it has defined his defenses in the past. Will it still?

The Chiefs open training camp in St. Joseph with quarterbacks and rookies reporting Friday and the full team arriving in the middle of next week. Even when the complete 90-man roster arrives, the defense will be replacing six players who started at least 11 games last season. That’s more than half the lineup.

These extra few practices offered to rookies have rarely felt this important for this defense because, well, it’s been a while since rookies were this important to this defense.

Four years, to be exact.

In 2022, the year in which the Chiefs devoted nearly an entire draft to remodeling their defense, they needed to replace four of their 11 starters. As it turned out, they devoted playing time to even more than four rookies. It was six draft picks who played at least 250 defensive snaps, the most in the NFL that year (and tied for the most in any season since 2012).

In the three years since, though, the Chiefs have offered at least 250 snaps in a season to just four rookies - that’s across the three seasons combined. They instead relied on experience, and they turned that into three consecutive years ranked top-10 in yards allowed - the first time that’s been true in the franchise’s history since the early 1970s.

It’s not about the NFL experience but rather the experience playing in the system - the experience with Spagnuolo. That’s how you call a blitz you’ve never called before. It’s how - and when - you layer on top of a foundation that has long been set.

This year? It’s going to be difficult to implement the same complexities, at least early on. Spagnuolo is not going to just stop blitzing. But it might be a bit harder to take teams by surprise when nearly half of his starters will still be learning the basics during camp at Missouri Western State over the next month.

The makeover won’t exclusively fall to rookies - defensive tackle Khyiris Tonga, safety Alohi Gilman and second-year player Nohl Williams have inside track to prominent roles. But the rookies will play a big part.

They better, anyway. The Chiefs spent a lot of draft capital on the defense. They traded up for LSU cornerback Mansoor Delane at No. 6 overall; they added defensive tackle Peter Woods at the end of the first round; and they plucked R Mason Thomas eight picks into the second round. They also took nickel cornerback Jadon Canady in the fourth. They need the rookies to play.

Can the defense still operate at a high level?

It’s been four years since that answer so heavily relied on rookies. And back then the reply was fluid, by the way.

When the Chiefs last asked more than two rookies to shoulder some of the load - that 2022 season - they allowed 369 yards per game in the first seven weeks.

Then came the bye.

Then came the improvement.

The Chiefs allowed 299 yards per game over the final 10 weeks, 70 yards fewer. That group won a Super Bowl. They grew. And more to the point, the scheme grew along with them.

It’s not that the Chiefs were necessarily patient. It’s that they had no other option.

That’s the similarity in St. Joseph. This group will be green early.

The last one still cashed in late.