MLB All-Star - Lesson 05 - Predicting Scores

Jonathan Bales is the author of Fantasy Baseball for Smart People—a 197-page book created to help you win playing daily fantasy baseball on DraftKings.

I first became interested in daily fantasy sports in late-2012. I was extremely bullish on the industry and where it was headed—at that time it was 10x smaller than it is today—so I decided I had to write a book about daily fantasy sports.


The only problem is I didn’t know anything about it. I was probably an average player at the time, and although I was able to parlay my knowledge of season-long fantasy sports into a bit of success, I don’t think I was a long-term profitable player.

I decided I needed to get in touch with players who were already winning. I spoke with a bunch of them, and I was shocked at how often they utilized a trick to project players that I hadn’t even considered: examining the Vegas lines and odds. Some daily fantasy players used the lines more than others, but for some of the best, the Vegas lines were and still are a fundamental component of their research.

This concept really hit home with me, and I’ve been one of the biggest proponents of using Vegas odds in daily fantasy sports research since that time. I’ve done a ton of research showing how Vegas has been accurate in the past, but I want to quickly discuss why we can and should trust the Vegas lines.

Why Vegas Can Be Trusted

There’s a common misconception that Vegas sets odds solely to balance action—that they want an even number of bets on each side of a line. That’s not really the case anymore; it might have been when bettors as a whole were poor, but nowadays, there are so many sharp bettors with massive bankrolls that Vegas can lose a lot of money if they put out a weak line. The market has become more efficient, and the Vegas lines have done the same over time.

Ideally, balancing money on both sides of a bet is great because it ensures a profit for Vegas. But again, it’s also risky because, if they knowingly post a weak line, it can get hammered by sharp bettors. Thus, the easiest and safest way for Vegas to make money long-term is to post accurate lines. If the odds are on point, they won’t get beat over the long run and they won’t expose themselves to the massive downside that can accompany a really weak line.

And if you think about it, we should generally be trusting those who put their money where their mouth is, right? That’s why daily fantasy players as a whole are generally an extremely knowledgeable bunch; if you’re putting your money on your beliefs, you have a clear incentive to be correct. And no one has more money on games than Vegas. With such a clear incentive to be right, we can trust the oddsmakers and their sophisticated algorithms.

In baseball, there are a variety of ways that we can use the Vegas odds to our advantage. The odds are actually the first place I start my daily fantasy baseball research because they’re that important to me.

Projected Runs

The first way to utilize the Vegas lines—and the most common—is to see how many runs they have projected in a game (and how many runs they’re projecting for each team). The more runs a team is expected to score, the higher their upside.

I’ve heard arguments that run projections and fantasy projections are different from one another and don’t correlate. That’s not true. I examined the historic accuracy of the Vegas lines in predicting fantasy production.


Up until 9.5 runs, the Vegas lines almost perfectly predict fantasy production on DraftKings. I’m not entirely sure why teams have more fantasy upside once a game reaches a total of 10 runs or more. It could be that the types of teams in that sort of matchup—perhaps explosive offenses versus poor pitchers or in hitter-friendly parks—have occasional games in which they explode for a ton of runs and fantasy production, throwing off the average. I’ve done other research to suggest that certain teams—those generally projected well by Vegas—are far more likely than others to have the occasional offensive outburst.

Either way, the conclusion is clear: target players on teams projected to score a lot of runs, especially in games with a double-digit total.


The moneyline is a number that represents how likely a team is to win a game. The lower the numbers, the bigger the favorite. A team with a moneyline of -250 is very likely to win, whereas one with a moneyline of +250 is likely to lose.

I think the moneyline has the most value for pitchers. Even though pitcher wins aren’t incredibly important on DraftKings, wins are obviously correlated with other positive events; when a pitcher gets a win, he typically throws a lot of innings, allows few hits, and perhaps strikes out a decent number of batters.

Thus, the moneyline can be used as a proxy for pitcher fantasy safety and upside; when a pitcher is extremely likely to win a game (and the opponent is projected poorly in terms of runs), that’s a great sign for his fantasy potential.

Player Props

One of the most underutilized aspects of the Vegas lines are player props—over/unders for players in different statistical categories. There are props for just about every player and stat in the NFL, where you can quickly see how many receptions and yards Calvin Johnson is projected to have in a given game, for example.

Since there are more relevant offensive players in baseball and because it’s a daily game, there aren’t always props offered for every player. However, most of the league’s stars have props posted each day, so you can quickly get a sense of who Vegas likes in each matchup.

Props have the most use for starting pitchers. Since only a handful of pitchers start in a given day, you can generally find props for all of them. The most important of these is of course strikeouts. A strikeout prop is basically Vegas’s prediction for how many strikeouts a pitcher will throw, which is extremely valuable information, especially on DraftKings.

I balance the moneyline with strikeout props to get a quality combination of a high floor and a high ceiling.

Line Movement

Finally, the way that the lines move as bets come in can be very telling for daily fantasy players. When the moneyline in a game moves from -150 to -200, for example, that’s generally a really favorable situation for the pitcher on that team.

I particularly take note when Vegas moves a line in the opposite direction of public betting trends. If 80 percent of the public is betting against the White Sox and they steal move to become bigger favorites, that’s a sign that some of the sharp money is on Chicago. When Vegas and sharp bettors agree—as can be indicated by a reverse line movement—that’s a situation with which you should generally align yourself as a daily fantasy player.

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Continue Reading MLB Training Camp

MLB All-Star – Lesson 01 – Using MLB Lineups
MLB All-Star – Lesson 02 – Hot and Cold Streaks
MLB All-Star – Lesson 03 – Importance of Left/Right Splits
MLB All-Star – Lesson 04 – Ballpark Factors
MLB All-Star – Lesson 05 – Vegas Lines

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