Lionel Messi is set to play at M&T Bank Stadium. Beware of field invaders.

Lionel Messi looked unfazed as the madness, once again, unfolded.

Several fans had scurried from the stands onto the playing field during an exhibition in Puerto Rico last week, their sights set on the man with the famous left foot. One took a selfie with Messi. Another sought an autograph. A third ripped his own shirt off and wrapped his arms around the superstar.

The unique obsession with the 38-year-old Argentine soccer legend is such that Messi mania regularly spills onto the pitch — and it’s something to watch for during his first-ever game in Baltimore on Saturday.

Messi’s club, Inter Miami, will face D.C. United at 4:30 p.m. in the first-ever Major League Soccer match played in Baltimore. M&T Bank Stadium is well-suited for celebrity: Its capacity of 70,000 is more than three times as large as United’s Audi Field in Washington.

The Maryland Stadium Authority, which owns the stadium, is aware that one of the world’s most beloved athletes is likely to be in Baltimore. They can’t exactly show their entire security playbook, though.

Each event is different, said Vernon Conaway Jr., the authority’s head of security, and preparations are “dynamic.” Field rushers are a consideration for any game, he said, though he declined to specify how officials mitigate such risks.

“We will have additional field security on the field, both in uniform and in non-uniform capacities,” he said in an interview Tuesday.

Messi, accustomed to field invaders, is often agreeable during the brief interactions. He’ll shake the fan’s hand or acquiesce to a selfie request.

Afterwards, though, the trespassers face legal ramifications.

If someone were to dash onto the field Saturday, security would detain the individual, place them in a holding cell within the stadium (there are several) and “turn that individual over to the Baltimore Police Department for processing of criminal charges,” Conaway said.

They’d also be banned from MLS events and potentially NFL games, too.

Dan Donovan, founder of Stratoscope, a security company that works with pro sports leagues, said guards who patrol a field’s perimeter look for “anomalies” in the stands. They use surveillance, too.

Not unlike a sports team, security also might run drills ahead of time. Guards are reminded to know their assignment: If there is a field invader, the entire fleet of security personnel can’t chase after them.

“You don’t want to have everybody from one side go after this individual, and then you’re vulnerable for another intrusion,” he said.

The public never hears about most potential trespassers, Donovan said. Only about 1 in 10 attempts are successful, he estimated, with the rest nipped in the bud before a fan can even get close to the action.

M&T Bank Stadium has seen its share of celebrities and powerful figures. Taylor Swift attended a game in 2024, and President Donald Trump was there a few months ago. In addition to Ravens games, the stadium will host six special events this year — the most in its three decades of existence.

With respect to Lamar Jackson and upcoming performances by K-pop group BTS, few people in the world command Messi’s stardom.

At 5-foot-7, he isn’t physically imposing, and he’s not much of a showman with the media, either. Still, he’s perhaps the greatest to ever play the world’s most popular sport.

Fans have sought to get close to Messi throughout his 21-year professional career, but there’s been a spike since he joined MLS in 2023, his security guard, Yassine Cheuko, has said.

There used to be about one instance a year, but in his first 20 months in the U.S., 16 people invaded the pitch, Cheuko said last May, according to several media outlets.

Cheuko has gone viral for his on-field sprints to stop fanatics from encroaching upon the world’s third-highest-earning athlete. The bodyguard was not permitted on Inter Miami sidelines last year, he has said, but recently captioned an Instagram photo “Guess who’s back,” following a Miami game in Orlando. (Evidence of Messi’s megastardom: His bodyguard has 1.4 million Instagram followers.)

Inter Miami and a representative for Cheuko did not reply to requests for comment. Neither did D.C. United or MLS.

One field-storming fan called her stunt the best day of her life. Another kissed Messi on the forehead. In Puerto Rico last week, a security guard tackled the shirtless fan who embraced Messi, domino-ing the star to the ground.

How often do these incidents happen? The Miami Herald has joked that Cheuko, the bodyguard, has spent more time on the field than some Inter Miami backups.