When Lionel Messi made the fateful decision to join Inter Miami CF last season, it not only instantly elevated the game of his new club, but also immensely raised the profile of 30-year-old Major League Soccer.

So it should come as little surprise that the American sports betting industry, another emerging entity, saw huge action surrounding the all-time soccer great and his squad in South Florida. Chris Schlosser, MLS' senior vice president of emerging ventures, told ESPN that the league saw record betting handle last year with "really nice growth across the major books" from 2022 to 2023.

Last summer, Messi -- along with former Barcelona teammates Jordi Alba and Sergio Busquets -- arrived in Miami to a team that was at the bottom of the league standings and would need a minor miracle to make it into the MLS Cup playoffs, which it ultimately failed to do.

Going into 2024, Messi & Co. brought in another former Barça superstar, Luis Suárez, to bolster what is now the undisputed most-talented team in the league. It has Inter Miami sitting as the clear-cut favorites to win MLS Cup this season, showing odds of +300 at ESPN BET, with some shops offering odds as short as +250.

BetMGM has a league-leading 15.1% of its MLS futures tickets on the Herons, while DraftKings reports an eye-popping 83% of bets and 81% of handle. Anticipating the hype around Messi's squad, DraftKings' director of race and sportsbook operations Johnny Avello and his team claim that they released MLS Cup futures before anyone else on the sports betting market.

"Last year when Messi came to Miami, they really had no chance to win it all, very slim chance," Avello said. "We took a bunch of action on them even at that point. So, yeah, I'm not surprised."

Inter Miami is, of course, receiving a ton of attention at the only legal online sportsbook in Florida, Hard Rock Bet, which reports that the Herons have roughly three times as much money on them to win the championship than the next-closest club, Orlando City.

However, not everyone believes Inter Miami is the team to beat this season. FanDuel reports that the club ranks second in its betting splits with 18% of the bets and 19% of the handle, trailing FC Cincinnati (24% of bets and 32% of handle).

In fact, other MLS teams with considerably less hype than Miami are attracting sharp action at the books: BetMGM reports that Colorado, Columbus, Orlando, Portland and Cincinnati are its biggest liabilities.

"Messi and Miami are going to take a lot of bets," BetMGM trading manager Seamus Magee said via email. "We don't try to book around what we need, we go by what our sharpest bettors are telling us. But Messi showed last year, almost simply by taking the pitch, that he can transform the way a team plays around him in this league."

Being the big favorite is nothing new for the Argentine legend: From 2009 through 2021, any time Messi's Barcelona was favored to win LaLiga, they were in negative money, with -167 in 2011-12 representing the club's largest preseason favorite status of the era, according to ESPN Stats & Information.

That said, European top-flight soccer is notorious for disparity -- Manchester City opened this season as around a -175 favorite to win the Premier League, for example -- whereas MLS is part of an American sports ecosystem that has systems in place (i.e. playoffs, drafts, salary caps) to promote parity. For comparison, the Los Angeles Dodgers are +400 to win the 2024 World Series, while the Boston Celtics entered this season at +380 to win the NBA Finals.

"Miami is not a sure thing at 3-1 to win it all. If they were a sure thing, they would be minus or even money, but they're not," Avello said. "This is where they belong."

The biggest factor working against Inter Miami's odds to win it all is age. Messi is 36 years old, with Alba, Busquets, and Suárez all in the same neighborhood; soccer players of that age don't tend to go injury-free for an entire season.

The second biggest factor is the schedule. Aside from the MLS regular season, Inter Miami will also contend games in the Concacaf Champions Cup and the relatively new Leagues Cup, which features teams from MLS and Liga MX. Messi is also still playing for Argentina, which will be fighting to win the prestigious Copa América this summer.

It all adds up to Messi and his former Barcelona compatriots not playing as much as Miami may want them to this year -- meaning the rest of the team will need to pick up the slack.

"If Messi gets hurt, their odds will plummet. If they are pumping teams by three or four goals with their full lineup, you will probably see their odds get shorter," Magee said. "Messi isn't the question mark on this team. ... It's going to be interesting to see how they navigate those [cup] matches and Messi's absence during international games."

Regardless of Inter Miami's performance this season, there's one clear winner here: MLS.

"The best part about all of this is it gives another angle for people to be talking about the game, the league, the season ahead, and this debate on whether Miami's odds are too high, too low, just right," Schlosser said. "We generally really think sports betting can help improve the fan experience and make fans more engaged with our matches."