Major League Baseball (MLB) has issued a directive prohibiting players from engaging in baseball-related event contracts on prediction markets such as Kalshi and Polymarket. The memo, reportedly sent out near the end of the 2025 season, emphasizes the league’s longstanding rules against betting on baseball games. The announcement coincides with serious legal issues facing two Guardians pitchers, Emmanuel Clase de la Cruz and Luis Leandro Ortiz Ribera, who are charged with conspiracy related to wire fraud and bribery in connection with betting schemes.
The memo, dated August 26, 2025, was issued by the office of Commissioner Rob Manfred and distributed in collaboration with the players’ union. It explicitly instructs players to refrain from participating in “prediction markets” or wagering on any outcomes tied to MLB games. It notes that activities associated with these markets violate the league’s betting rules.
According to reports from Front Office Sports, the memo included information about various companies, including Kalshi, Robinhood, and Crypto.com, which offer platforms allowing users to wager on the outcomes of sporting events. The existence of these prediction markets had “recently come to our attention,” the memo stated, despite Kalshi having launched its MLB markets on April 16, 2025, well before the memo’s circulation.
While the memo has been confirmed by sources within multiple MLB clubs, its message is still gradually reaching players across both major and minor leagues. The memo was distributed widely and even posted in visible areas near locker rooms to ensure players were aware of the restrictions.
MLB’s Cautious Approach to Prediction Markets
Despite Major League Baseball’s recent embrace of online sports betting, collaborating with organizations like the NBA and the PGA Tour to advocate for legalization, the league has opted for a cautious stance regarding prediction markets. This strategy stands in contrast to other leagues such as the NHL, which has already formed alliances with Kalshi and Polymarket.
The NFL has voiced concerns over the lack of regulatory oversight of prediction markets, suggesting that their offerings resemble traditional sports betting. Furthermore, the NBA is currently grappling with a significant gambling scandal involving a current player, a coach, and a former player and coach, prompting increased scrutiny over how leagues manage these issues.
On December 3, 2025, NFL Commissioner Roger Goodell reiterated the league’s reluctance to engage in prediction markets without a solid regulatory framework. During an event with Genius Sports, he remarked, “For us, that’s not something we’re about to enter into. We are going to see how things play out, both from a regulatory standpoint… There are a lot of legal challenges going on right now.”
MLB’s memo underscores the league’s commitment to maintaining the integrity of the game while navigating the evolving landscape of sports betting. As the legal landscape around betting and prediction markets continues to develop, MLB’s stance reflects a broader hesitance among professional sports leagues to fully embrace these new wagering platforms.
The league has yet to respond to requests for comments from various media outlets regarding the implications of the memo and its ongoing relationship with the betting industry. As players and fans alike adapt to these changes, the future of sports betting in baseball remains a topic of significant interest and concern.
