The run line is baseball's version of the point spread.
While most MLB betting is done via the moneyline – picking which team will win the game outright – sportsbooks also offer baseball’s version of a point spread: the run line.
What is a run line?
A run line is a variation of baseball betting odds used to level the competitive difference between two teams by instituting a handicap – just like a point spread. The stronger team must win by more runs than the designated handicap (most often 1.5 runs) in order to be graded as the winner while the weaker team must win outright or lose by less than that designated number of runs.
How run lines are set
With the majority of MLB games decided by slim margins, and 29 percent of all total games decided by just one run (705 of the total 2,430 games played in 2019) most run lines have a spread of 1.5 runs and are used to level the playing field between two teams. Many factors go into the MLB run lines, such as starting pitchers, overall and recent team performance, and home/away splits.
The team with the higher implied probability of winning the game – or the favorite - will have a run line of -1.5, which means they have a handicap of 1.5 runs and must win by two or more in order to be graded the run line winner. The team with the lower implied probability of victory – or the underdog - will have a run line of +1.5, which means they’ve been given 1.5 extra runs and can lose by one run or win outright to be graded the run line winner.
There’s also a set of odds associated with each team’s run line, more commonly known as the juice, vig, vigorish or price, which is calculated based on each team’s implied probability of covering their assigned run line (-1.5 or +1.5). This is most often found next to the 1.5-run spread and displayed by American odds inside brackets.
Run line favorite -1.5 (+140)
Run line underdog +1.5 (-160)
How to read run lines
Here’s where it can get tricky for those new to MLB run line betting: while a team may be set as a run line favorite at -1.5, covering that spread is harder than winning outright, based on the matchup. Therefore, that team winning by two or more runs has a lower implied probability. That’s why it’s common to see a run line of -1.5 being set with positive or “plus money” vig.
On the other side of the diamond, a team with a +1.5 run line could have a higher implied probability of covering depending on the difference in skill between the two clubs. That means the vig attached to the +1.5 could be set with negative or “minus money” vig.
For example, the New York Yankees are hosting the Toronto Blue Jays in the Bronx. The Yankees have the higher implied probability to win outright and are then set as 1.5-run favorites on the run line with the vig priced at +140 – you can win $1.40 for every $1 wagered or $140 on a $100 bet.
The Blue Jays have a lower implied probability of winning outright against a superior Yankees team on the road, and are deemed +1.5 run line underdogs with the vig attached set at -160 – you need to wager $1.60 for every $1 you want to win or win $48.08 on a $100 wager.
If the Yankees beat the Blue Jays 5-4, they fail to cover the -1.5 run line despite winning outright and run line bets on the Yankees -1.5 are graded as a loss and run line bet on the Blue Jays +1.5 are graded as a win. However, if the Yankees beat the Blue Jays 6-4 they would not only win the game outright but cover the 1.5-run spread, grading those Yankees -1.5 bets as a winner and grading bet on Blue Jays +1.5 a loss.
Run line movement
Like all sports betting odds, MLB run lines and the vig attached to them aren’t static or the same across all sportsbooks. However, it is rare for a bookmaker to move off the 1.5-run spread and it’s more common to see the vig/juice adjusted for both sides.
Bookmakers will constantly adjust those run line prices in order to balance the handle (total amount of money bet on a game) on either side to limit the books’ liability. If a sportsbook has even handle on both teams, it guarantees a profit regardless of the final result.
For example, if the Yankees run line of -1.5 opens at +140 and takes most of the money being bet on the run line odds, bookmakers could move the vig down (perhaps to +130) while also adjusting the Blue Jays’ +1.5 vig as well (moving to -150), in order to entice bettors to wager on the side with the smaller percentage of the handle – hence spreading the overall game handle between the two teams.
Whatever run line odds you place your bet at are the odds you bet is graded on, regardless of where the moneylines may move before the game starts. If you bet $100 on Yankees -1.5 (+140) earlier in the day and the price moves all the way to +120 in the hours before start time, your wager will be graded and paid out at the +140 vig that was available at the time of your bet.
Run line betting strategy
One of the best times to bet the run line is when dealing with larger moneyline favorites (odds to win outright). You may not want to bet a -250 moneyline favorite (which would return just $40 of profit on a $100 bet) but if you're confident that the favored team will win by two or more runs, you can get a much higher return in profit by laying the -1.5 runs and betting the less-expensive vig/juice on the run line favorite. It does, however, come with a lower implied probability than the standard moneyline, hence the higher payout.
As mentioned above, the vig/juice for MLB run line odds is constantly being adjusted as bookmakers react to bets coming in as well as other influences such as injuries, lineups, and trades. Bettors trying to get the most from their run line betting picks should be aware of the opening odds and where those run line prices are moving before game time.
Depending on which side of the run line you want to bet on, you may want to place your run line wager early or wait until closer to the start time to make your bet. If you like a run line favorite and see the vig on the +1.5 underdog getting bigger, you could be patient with your wager and get a better price on the -1.5 favorite later in the day. You can use Covers’ MLB odds and line history to monitor various betting markets and plan the best time to place your MLB run line picks.
Another strategy to keep in mind when betting run lines is to be cautious picking too many +1.5 underdogs with high-priced vig (-150 or higher). As explained above, the vig/juice attached to the run lines can have a negative value (-), also known as “minus money” odds, and payout less than the original amount bet and while those run line underdogs often have a higher implied probability of covering the 1.5-run spread, there’s no guarantee that they will do so.
A $100 bet placed on a +1.5 run line underdog at -180 will return a profit of just $55.55. If you were to bet $100 on five +1.5 run line underdogs at -180 odds each ($500 bet in total) and won three of those five betting picks, you would lose $33.35 overall – despite going three for five with your wagers. Even winning four of those five big moneyline favorite bets would only turn a profit of $122.20 from the initial $500 risked.