Common Mistakes in MLB Betting and How to Avoid Them

The top mistake bettors make is ignoring value and probability, instead betting on favorites or streaks without comparing the odds to the true likelihood of the outcome. To succeed in the 162-game season, you must adopt a disciplined, long-term approach focused on finding edges where the bookmaker has mispriced a game.

Mistake 1: Misunderstanding Odds and Laying Too Much Juice

Novice bettors frequently fall into the trap of betting on heavy favorites (e.g., odds of $-200$ or worse), assuming a guaranteed win. This is a losing strategy over time.

The Problem: Poor Value on Favorites

A team at $-160$ only needs to win roughly $62\%$ of the time to break even. Historical data shows that betting on all steep favorites at that price or higher often results in a loss of units over a full season because the small payouts don’t cover the losses from upsets. The high commission (vig) on these lines erodes any potential profit.

The Solution: Focus on Expected Value ($\text{EV+}$)

Only place a bet when your estimated true probability of an event happening is greater than the implied probability of the posted odds. This is called a value bet.

Actionable Step:

1. Estimate True Probability: Use advanced statistics and research to determine the true probability of Team A winning (e.g., you calculate it at $65\%$).
2. Calculate Implied Probability: Convert the bookmaker’s odds (e.g., Team A is $-160$, implying a $\approx 61.5\%$chance) into a percentage.
3. Find the Edge: Since your $65\%$ is greater than the book’s $61.5\%$, you have a $\text{EV+}$ edge and should place the bet.

Avoid: Betting solely on a team because they “should win.” Always check the price first. Avoid laying more than −160 unless your analysis shows an exceptionally large edge.

Mistake 2: Overrelying on Starting Pitchers (Tunnel Vision)

The starting pitcher (SP) is important, but obsessing over an ace while ignoring the rest of the team is a common oversight.

The Problem: Inflated Ace Prices

The public often heavily favors high-profile aces, causing oddsmakers to inflate their team’s moneyline odds (e.g., to $-200$or worse), which offers poor value. Furthermore, even elite hurlers can get shelled on any given night due to baseball’s high variance.

The Solution: Integrate the Bullpen, Lineup, and Splits

Successful betting requires a holistic view of all nine innings and the entire roster.

• Bullpen Strength: A great outing by the SP can be wasted by a weak or overworked bullpen. Always check recent bullpen ERA and recent workload (which relievers were used yesterday?) before placing a bet.
• Lineup Depth: Do not overreact to the absence of one star player. A deep MLB lineup can often overcome a slugger’s absence more easily than in other sports. Evaluate the entire lineup’s on-base percentage (OBP) and slugging power.
• Pitcher Splits: Compare the SPs objectively using advanced stats like FIP (Fielding Independent Pitching) and look at their Home/Away splits. Sometimes, the underdog has the better value pitcher on the mound. Consider First Five Innings (F5) bets to isolate the starting pitching matchup and eliminate bullpen risk.

Mistake 3: Betting with Emotional and Cognitive Biases

Allowing personal feelings, team loyalty, or short-term results to drive wagers is a recipe for long-term loss.

The Problem: Fandom and Recency Bias

• Emotional Betting: Betting on your favorite team or home team at any price, ignoring that odds for popular teams (like the Yankees or Dodgers) are often inflated due to public money.
• Recency Bias: Overweighting a recent winning streak (e.g., “they just won five in a row, they’re hot!“) or loss. These streaks often reflect small-sample luck or weak competition and are not predictive of the next game’s outcome.

The Solution: Bet Numbers, Not Teams

• Maintain Objectivity: Treat every game as an independent event. Stick to your statistical model and your calculated Expected Value, regardless of team loyalty or recent results.
• Respect Variance: Avoid the gambler’s fallacy (the belief that a team is “due” for a win after a loss). Baseball has high variance; even the best teams lose over $60$ games a season.
• Buy Low, Sell High: Be wary of teams the public loves and are riding a streak. Value is often found in undervalued underdogs or teams coming off a non-predictive loss.

Mistake 4: Poor Bankroll Management and Chasing Losses

Discipline with your capital is the most critical factor for long-term survival in the high-variance MLB season.

The Problem: Wildly Varying Stakes

Many bettors lack a dedicated plan, betting haphazardly or dramatically changing their stake size based on recent outcomes. This leads to chasing losses, irrationally increasing wager size after a bad beat to try and “get even,” which often leads to a spiral of greater losses.

The Solution: Flat Staking and Strict Tracking

Define a Unit: Determine a fixed percentage of your total bankroll as your betting unit, typically 1% to 3%. Never bet more than this on a single wager.

• Example: For a $\$1,000$ bankroll, one unit is $\$20$ (2%). Stick to this amount even if you lose five bets in a row.

Flat Betting: Maintain a consistent unit size. Do not increase your stake after a win (overconfidence) or decrease it after a loss (panic).

Track Everything: Maintain detailed logs of every wager (odds, stake, result, and rationale). This discipline helps you objectively review your strategy and spot costly behavioral biases.

Mistake 5: Failing to Line Shop or Account for External Context

Accepting the first odds you see or ignoring critical situational data leaves money on the table.

The Problem: Overpaying for the Bet

Odds vary between sportsbooks. Using only one book means you often overpay the juice or miss out on a more favorable spread. Even a small shift from $-150$ to $-140$ significantly reduces your required break-even win rate over time.

The Solution: Check Every Factor, Shop Every Line

• Line Shopping: Use odds aggregators (or multiple sportsbook accounts) to compare moneylines and totals and ensure you always get the best available price before placing a bet.
• Ballpark and Weather: Always factor in the venue and local conditions. Wind blowing out or hot, humid air often favors the Over on the total, while cold weather favors the Under.
• Travel and Rest: Check the schedule for situational factors. A West Coast team finishing a multi-city road trip on the East Coast may be fatigued and prone to underperforming expectations.
• Advanced Stats over Surface Stats: Don’t trust traditional metrics like ERA blindly. Use advanced metrics like FIP (Fielding Independent Pitching) to see if a pitcher’s low ERA is due to luck. If a pitcher’s actual ERA is much lower than their FIP, they are likely to regress soon.