Official betting is a key component of sportsbooks. The game must be official for all bets to pay, including totals and moneyline bets. Similarly, all players must participate for player props to have action. Generally, the number of pitches thrown by pitchers and plate appearances made by position players will determine whether a prop is deemed to have action. These rules apply to pre-game, in-game and live bets.

All bets must be placed before the scheduled start time (local stadium time) for a game to be considered an official game. This includes bets on the total number of runs scored in a game. If a game is shortened or suspended, bets on the Over/Under are void unless the amount of runs scored in extra innings counts toward the overall scoreline.

For head-to-head player props, the players involved must be in the starting lineup and the game must be official for those bets to stand. Inning bets, however, are void if the game is called during that inning and the official score reverts to the previous inning.

NRFI bets, on the other hand, will only have action if the selected team scores at least one run and completes three outs in a single inning. NRFI bets will also be void if the selected team is leading at any point during the inning. These are the general rules for MLB games, but some sportsbooks may have specific policies regarding NRFI and other types of bets.