Some 52 weeks ago, NFL personnel stood inside Estadio Azteca in Mexico City, studying the aftermath and playing-surface wreckage from a pop star's concert. The damage was unsalvageable, the field unsuitable for football, and they determined they'd need to move the game back to Los Angeles. Too much work. Too much destruction. And too little time.

Only days afterward, NFL leadership met with stadium and Mexican government officials. Together, they analyzed what had gone wrong before the conversation shifted to another avenue.

What about another shot at a game in 2020?

"While the decision was made last year that the field wasn't playable, that same week, NFL leadership, in partnership with Televisa, who owns the stadium, and the Mexican government, we were making commitments to come back next year," said Damani Leech, the NFL's chief operating officer of international competition.

Next year has arrived.

On Monday night, the Chiefs will travel south of the American border into Mexico and face the L.A. Chargers in an AFC West contest tallied on the schedule as a Chargers home game. Unlike a year ago, when the field prompted relocation on just six days' notice, this game will take place in its planned site.

Because this one came with some added conditions. With some assurances.

In that meeting days after last year's fiasco, the NFL insisted on several terms before agreeing to return, Leech said, highlighting three of them as the most notable.

1) They would hire a field consultant to take monthly visits to Mexico City to check on the field. He or she would collaborate with stadium management and return with pictures, detailed reports and recommendations.

2) Volume. Televisa would scale back the events it hosted leading up to Monday's game, reserving the stadium only for regularly-scheduled soccer matches as the football game drew near.

3) A backup plan. Together, the organizations would plant a sod farm nearby. If needed, the farm would be used to replace patches of the field or the entire 120-yard playing surface.

Together, these things formed the blueprint for what the Chiefs and Chargers are prepared to encounter Monday -- a field ready for the rigors of an NFL game.

"Our field rep has been in contact with the league, who's been in contact with the representatives in Mexico City taking care of the field," Chiefs owner and CEO Clark Hunt said. "It's a completely different field, and it's in much better condition than it was last year."

That, too, derived from a change in approach. Estadio Azteca replaced its playing surface this summer, returning to traditional natural grass after installing a hybrid mix in 2018. The stadium also installed a new irrigation and drainage system in the spring. It's worked well enough that the sod farm -- the Plan B -- hasn't been needed, Leech said.

Officials from both the Chiefs and Chargers visited the field, standard protocol on international games. The response has been a proverbial thumbs-up.

The stadium held up its end of the bargain, clearing its concert schedule from August through November. It hasn't hosted a soccer game there in two weeks, despite being home to Club America along with the Mexican national teams. And the league has stuck rigidly to its plan -- constant oversight with the newly-hired field consultant.

The NFL's opportunity in Mexico

That's the how.

The why: Money. And opportunity.

The NFL sees a growing and undertapped market in Mexico. Four of the NFL's highest single-game attendance totals in league history came at Estadio Azteca, though the venue's 2016 renovations reduced its capacity.

According to Hunt, for nearly a decade, the league has considered increasing its international footprint in the form of more games. The topic is already part of the next collective bargaining agreement discussions, he said, including the possibility of adding a regular season game in exchange for the subtraction of one or two preseason games, which would give every team eight regular season home dates, eight on the road and one neutral site date.

"It would give the league more inventory to play more international games," Hunt said.

While London has received the influx recently, the appetite appears present in Mexico. Leech said the league's research has shown there are 22 million NFL fans in Mexico. It further categorizes one-third of those as "avid football fans."

"I think it's a tremendous market for us, and there's a lot of opportunity," Leech said. "So while there are over 20 million fans here in Mexico, we think there's great opportunity to increase that number over time. And certainly having games in that market is a great way for fans to touch and feel and experience the NFL. But we're constantly looking for other ways, as well, to connect with those people."

The stadium is expected to be full Monday, offering an environment unique in comparison to NFL home stadiums. When the Chiefs played in London in 2015, they noticed the blend of fans occupying the seats. Some rooted for them, others against them.

And many were there without a rooting interest, simply taking advantage of a rare chance to see an NFL game.

"There's a buzz that takes place throughout the whole game," Chiefs coach Andy Reid said. "There's noise, which is great. That's a good thing. I think that's equal for both teams. But you're going to have to deal with some noise. There are a lot of people in that stadium, and they're excited for both teams to be there, so there's going to be noise. We get that."

Just one year later than anticipated.