There are two ways to bet on a baseball team: taking them on the money line or on the run line. Some sportsbooks offer a third option called the alternative run line but that is a more sophisticated betting approach handicappers can take.
The money line is the generic bet in which a team has to win for a bet on them to be profitable. The run line is a different story. Betting a favorite on the run line means that the favorite would have to win by 2 or more runs. Alternatively, betting on an underdog on the run line means that the underdog has to win or lose by only 1 run.
Baseball gamblers love to bet favorites and the run line gives them an opportunity to convert the favorite into an underdog by adding the stipulation that they have to win by at least two runs. But there is a certain conversion that the sportsbooks do that go against the gambler.
First, they take the moneyline odds and then convert it into a run line. By sifting through years of data, they can calculate with extreme precision, the likelihood that a team winning a game would cover the run line. They then convert the game into a run line and devalue the odds against the novice gambler.
Experts say that if any gambler is so certain that a favorite can beat the run line that they’d be better off just betting them on the moneyline for a little bit more than losing the odds in the conversion.
Road winners cover the run line 80% of the time while home winners cover it 70% of the time. The reason for the disparity is that when a road team wins, both teams bat for 9 innings. When a home team wins, the home team likely bats just 8 innings, causing a slight loss in value.