Baseball has more ways for a bet to end strangely than any other major sport. Rain can end a game after five innings. A starting pitcher can be scratched an hour before first pitch. A hitter can be lifted for a pinch-hitter in the second inning. Regular-season extra innings start with a runner already on second.
Each of those has a rule in your sportsbook’s house rules, and the rule decides your bet before the score does. Here is how the standard rules at major U.S. sportsbooks work, and where books differ.
1. Rain-shortened games: the moneyline stands, totals usually don’t
A regular-season game becomes official after five innings, or four and a half if the home team is ahead. If weather ends it after that point, the moneyline is graded on the official result.
Run lines and totals usually need a full game: nine innings, or eight and a half if the home team leads. If the game is called earlier, those bets are void, unless the result was already decided.
Say rain ends a game after six innings with the home team ahead 5–2, seven runs in all:
| Your bet | Graded |
|---|---|
| Home team moneyline | Wins |
| Over 6.5 | Wins (already decided) |
| Over 8.5 | Void |
| Under 8.5 | Void |
| Home team −1.5 | Void |
The over 6.5 had already cleared, so most major books pay it. The under 8.5 was winning, but more runs could have come, so it had not been decided and is void. The same goes for the run line: a three-run lead is not a final margin.
- Postponed before first pitch: bets are void.
- Suspended and resumed later: bets stand if the game finishes within the book’s window. Several major books use 36 hours; check yours.
- Postseason: MLB plays every playoff game to completion. Weather suspends a playoff game and it resumes later, rather than ending early.
2. Extra innings count
Totals, run lines and player props all include extra innings.
A game is tied 3–3 after nine, and the under 7.5 is sitting at six runs. In the regular season, every extra inning starts with a runner on second base, so a single can score a run. One run in the 10th and the under still wins, 4–3. Two runs and it loses.
The automatic runner is a regular-season rule. Postseason extra innings start with the bases empty.
3. A scratched starter: game lines and pitcher props differ
The starting pitcher is often the biggest single factor in a baseball price, so what happens when one is scratched matters. Game lines and pitcher props follow different rules.
Game lines: “action” or “listed pitchers”
Most U.S. books grade moneylines, run lines and totals as action by default: the bet stands even if a different pitcher starts. Some books also sell listed-pitcher versions, which are void if a named starter does not start. If the starter is the reason you are betting, pick that version when you place the bet.
Pitcher props: he has to start
Strikeouts, outs and earned-runs props need the pitcher to start the game. If he is scratched, or pitches in relief behind an opener, the bet is void at most books. Once he throws the first pitch, the bet stands.
So suppose you bet a starter over 5.5 strikeouts. He feels something in his elbow and leaves after one batter. He started, so the bet stands, and it loses.
A change to the opposing starter does not void a hitter’s prop. If you bet a hitter’s over 1.5 total bases and the ace he was facing is scratched for a bullpen game, your bet stands. The change may help you or hurt you, but it is not a reason to void.
4. Hitter props: one plate appearance
For hitter props (hits, total bases, home runs, RBIs), several major books, including FanDuel and DraftKings, keep the bet live once the player gets one plate appearance. Some books require the player to start instead. A player who never comes to the plate is void.
That cuts both ways. A bench player who pinch-hits once and grounds out has had his plate appearance, so an over on his hits loses. A starter who is lifted after one at-bat is graded on that one at-bat.
Why this matters when you compare prices
Comparing prices only works when the bets are the same. A listed-pitcher price and an action price are not the same bet. Neither is a first-five-innings line and a full-game line. That is why our MLB boards keep first-five markets out of full-game comparisons, as our MLB methods explain.
When you shop a line, check that each book is selling the same bet first. Then the price difference means something.
A quick checklist before you bet
- Action or listed pitchers? Most books default to action.
- What if rain ends it early? The moneyline stands after five innings (four and a half if the home team leads). Run lines and totals usually need nine, unless already decided.
- Do extra innings count? Yes, for game lines and props.
- Pitcher prop: he must start, or the bet is void.
- Hitter prop: one plate appearance, or must he start? It depends on the book.
- Suspended game window: often 36 hours, set by each book.
Rules for other sports
- NFL betting rules: overtime, ties and player props
- NBA betting rules: overtime, player props and the player who sits
- NHL betting rules: overtime, shootouts and props
Related reading
- What Is Vig? How Sportsbooks Make Money and How to Remove It
- Playoff Strikeout Props: Books Leaned Under, Overs Cashed
- MLB methods
Frequently asked questions
What happens to an MLB bet if the game is called for rain?
If the game is official (five innings, or four and a half with the home team ahead), moneylines are graded on the result. Run lines and totals usually need nine innings, or eight and a half with the home team ahead, and are otherwise void unless the result was already decided.
Do extra innings count for MLB totals and props?
Yes. Totals, run lines and player props include extra innings, including runs scored by the automatic runner in the regular season.
What happens to a pitcher strikeout prop if the pitcher is scratched?
The bet is void at most books, because the pitcher must start the game. Once he starts, the bet stands even if he leaves early.
What does action mean in MLB betting?
An action bet stands no matter who starts on the mound. Most U.S. sportsbooks grade game lines as action by default. A listed-pitcher bet is void if a named starter does not start.
Does an MLB hitter prop stand if the player comes off the bench?
At several major books, including FanDuel and DraftKings, a hitter prop stands once the player has one plate appearance. Some books require the player to start. A player who never bats is void.
This guide describes common rules at major U.S. sportsbooks as of October 2026. Rules change and differ by book and state. Your sportsbook’s published house rules decide how your bet is graded.
← Back to Blog