Last December, MLB shared a memo warning the players about investing in the prediction market business. But it took MLB just three months to backtrack from its previous stance.

They have now got into a deal with one of the country’s leading prediction-market companies, Polymarket. This decision promises a massive payday for the league. But the move is already drawing the ire of the fanbase, especially toward commissioner Rob Manfred.

“Major League Baseball is getting into the prediction-market business through a multi-year deal with Polymarket,” Front Office Sports reported.

“Under the deal, Polymarket will become the exclusive prediction-market partner of MLB and will be the only platform allowed to use team logos and marks.”

The deal between MLB and Polymarket is rumored to be around $300 million over four years. Under the contract, Polymarket would have access to official logos, and fans across all 30 teams could invest based on their prediction. MLB is the latest pro league to join the prediction market bandwagon.

MLS, UFC, and NHL have already signed a deal with Polymarket.

But here’s the catch!

In the last few years, the prediction market industry has witnessed explosive growth, especially in the sports market. It is projected to reach $10 billion by 2030, up from a $3 billion annual run rate in early 2026. With the industry steadily becoming mainstream from being a niche, pro leagues are expected to line up for a deal.

But MLB’s traditional stance is what’s making all the news.

“Late in the 2025 season, Major League Baseball sent a memo directly prohibiting its players from engaging with baseball event contracts on Kalshi, Polymarket, and other prediction markets,” Front Office Sports reported back in December.

Even Manfred emphasized how their “No. 1 priority is to protect the integrity of the game.”

Fans wonder how MLB would maintain its ‘integrity’ now.

“I hope that it goes without saying that our primary concern, always first in our minds, is protecting the integrity of the game,” Manfred said. “I think in today’s world, it is really important not to be chasing developments but to try to be involved and in front of those developments because our world is so fast-moving.”

Clearly, MLB is trying to accept the evolution it was once infamous for not accepting, while also not sacrificing integrity. However, they just had a deal with the same $9 billion brand that was closed for the U.S. customers till last year.

In 2022, the Commodity Futures Trading Commission (CFTC) accused the brand’s event-based binary options market of violating federal regulations (unregulated derivatives-trading platform), leading to a settlement that banned U.S. users. To operate in the country, platforms must register with regulators, which Polymarket did not do initially.

Polymarket had a settlement with the CFTC in 2022, and they had to pay a $1.4 million fine for the same. Till 2025, they blocked the US market from using the platform. But then, they worked to align with the Commission for a potential return.

In November, the CFTC granted Polymarket an Amended Order of Designation, allowing it to operate as a regulated exchange.

But MLB fans are not impressed.

MLB’s deal with Polymarket has left the fans fuming

Fans are wondering what made MLB backtrack from its traditional stance on sports betting. “They spam betting companies all over the games, then treat players as the problem when they fall into gambling…. lol,” one fan said. The San Diego Padres’ infielder/outfielder Tucupita Marcano landed on the permanently ineligible list for violating the league’s sports betting rules and policies. Marcano bet more than $150,000 on baseball, with $87,319 of that on MLB-related bets.

“Rob Manfred is BRAINDEAD. Only going to make the gambling issue worse. They are going to kill off the MLB…,” another added.

In recent years, MLB has extensively embraced sports betting companies. They already have a partnership with companies like FanDuel and DraftKings. But while this increased revenue and fan engagement, it is a significant deviation from what MLB once stood for. Before 2018, sports betting advertisements were also banned in the ballparks.

“And they won’t put Pete Rose into the Hall of Fame is a tragedy,” another user remarked. Just last year, MLB lifted the Cincinnati Reds’ legend Pete Rose’s lifetime ban posthumously. Rose was banned for allegedly being actively involved in sports betting, and he has yet to get his spot in Cooperstown despite having a record of 4,256 hits.

“So why are the Guardians players in trouble now?” another one asked. Guardians’ Lusi Ortiz and Emmanuel Clase were banned last year. They were accused of conspiring to influence games by signaling pitch types (balls or specific speeds) to bettors, leading to hundreds of thousands of dollars in illicit winnings.

So, fans wonder, if MLB is embracing market prediction and betting as legal, why would the players be punished?

“Then we all put on our shocked faces when players get caught “predicting” games,” one fan agreed to the broader sentiment.

As MLB chases new revenue streams, it risks alienating a fanbase that sees the league compromising its core principles for profit.