Prop betting is causing unrest in the clubhouse.

The MLB Players Association is pushing to outlaw prop bets on individual players as concerns grow over gamblers harassing athletes, a union source told ESPN.

Amid ongoing collective bargaining talks with Major League Baseball, the MLBPA proposed a joint lobbying campaign with the league to ban player-focused bets at sportsbooks, daily fantasy platforms and even prediction markets, the source said. 

If adopted, this sweeping ban would wipe out wagers on anything from a batter hitting a home run to a pitcher’s strikeout total — whether placed pregame or in-game.

Through the rise of online sports betting, players have experienced online threats, messages demanding reimbursement and even in-person confrontation from disgruntled sports bettors.

An MLB official said the league plans to respond as negotiations continue.

The union also wants MLB to clear up language in the current labor deal so players can take endorsements from legal betting operators, including prediction markets. Unlike the NBA, NHL and UFC, MLB’s CBA bars players from using their name, image or likeness to promote wagering on ball games.

On top of that, the MLBPA wants changes to how gambling investigations are handled. Under its proposal, players under probe would be placed on administrative leave, and those serving gambling suspensions could be allowed a 15-day unpaid minor-league rehab stint near the end of their punishment.

The volatile nature of nine innings has made prop betting a more focused strategy to wagering on the game. Whether it be total hits, bases and outs recorded, prop bets offer bettors a sense of more control, using a player’s stats, matchups and recent play to target profits. 

In turn, prop betting has become a considerable slice of the betting market, accounting for an estimated 20 percent to 30 percent of wagers on games, according to ESPN’s sources.

This push comes as MLB tightens scrutiny of betting activity after two Guardians pitchers were indicted in an alleged pitch-rigging scheme tied to gambling. The league and its sportsbook partners later imposed a $250 cap on first-pitch prop bets and moved to restrict them from parlays.

The current collective bargaining agreement is set to expire on Dec. 1, 2026.