An increasing number of sportsbooks will allow you to play a first half, or five inning, bet. That bet has many of the advantages of the bets in football and basketball and can, in some cases, give the bettor more control over a betting situation.
The rules are fairly simple and are pretty much untouched compared to regular 9 inning baseball betting. The only glaring difference is all wagers are decided on the score after five full innings of play instead of 9. All first 5 inning or 1st half spreads list the starting pitcher so each team's named starter must start for the bet to have action. If a pitcher from either team doesn't start all bets are canceled before the game.
One of the great things about a five-inning wager is that it typically plays out to form more than a nine-inning game. The starting pitchers, which are usually the basis for any baseball wager, have more of an impact on the outcome in a five-inning game than they do in a regulation game, as the bullpen shouldn't come into play. If it does, you're probably in trouble, as that means your starting pitcher didn't last five innings, which will normally result in a loss.