MLB Betting Mistakes: The Ten Errors That Drain Your Bankroll Fastest

I have made every mistake on this list. Some of them I made for months before recognising the pattern, and a few of them I still catch myself drifting toward when discipline slips during a cold streak. The purpose of this article is not to lecture — it is to lay out the ten most common errors I see in my own betting and in the community around me, along with the specific fix for each one. If even two or three of these apply to you, correcting them will do more for your bottom line than any new system or model ever could. For the broader framework that ties these corrections into a complete approach, the MLB betting strategy guide covers the full picture.

Ten Mistakes MLB Bettors Make and How to Fix Each One

The first and most expensive mistake is blindly backing favourites. MLB favourites win roughly 57.5% of all games at an average moneyline around -142.6 in American odds, and a flat $100 bet on every favourite over a decade produced a loss exceeding $7,000. The fix is simple: never bet a favourite without first calculating whether the implied probability exceeds your own assessment. If the market says a team wins 60% of the time and you agree, there is no edge — the bookmaker’s margin eats the profit.

The second mistake is ignoring the starting pitcher. Baseball is the most pitcher-dependent major sport, and the moneyline moves significantly based on who is on the mound. Bettors who pick sides based on team reputation without checking the starter are betting on a different game than the one actually being played. Always confirm the starting pitcher and check his recent form, xERA, and platoon splits before placing any wager.

Third: chasing losses. A bet that loses in the seventh inning does not become a good reason to double your stake on the next game. The sportsbook hold rate reached 10.15% nationally in 2025, which means every additional impulsive bet costs you roughly ten pence per pound in margin before you even assess the matchup. The fix is a hard daily loss limit — I use two units — after which I close the app and do not bet again until the next day.

Fourth: betting too many games. With 15 games on many MLB slates, the temptation to bet eight or ten of them is real. But edge does not appear in every game. I rarely bet more than three games per day, and on some days I bet zero. The discipline to pass on a full slate is worth more than any marginal edge you might squeeze from game number seven.

Fifth: ignoring closing line value. Many bettors track their win-loss record obsessively but never check whether the odds they took were better than the closing line. CLV is the single best predictor of long-term profitability. If your CLV is consistently negative, you are taking worse prices than the market settles at, and no handicapping skill can overcome that drag.

Sixth: betting parlays as your primary market. Parlays are entertaining, but the bookmaker’s margin compounds with each leg. A four-leg parlay at a 10.15% hold per leg produces an effective hold above 35%. Parlays should be a small, recreational portion of your betting — not the foundation. Dr. Harry Levant of the Public Health Advocacy Institute has warned that the industry’s practices often operate without adequate safeguards, and the aggressive marketing of parlays to recreational bettors is one area where that concern is most visible.

Seventh: failing to account for weather. Wind, temperature and humidity directly affect ball flight and run scoring, and the market does not always adjust quickly enough when conditions change in the hours before first pitch. Check the weather forecast for every game where you are considering a total bet — it takes thirty seconds and can flip the value from one side to the other.

Eighth: not segmenting your results by market type. A bettor who is profitable on moneyline underdogs but losing on run lines may not know it unless their tracking system separates the two. This mistake causes bettors to keep placing losing bet types because their overall record looks acceptable. Segment by market, review monthly, and cut the markets where you have no edge.

Ninth: overvaluing recent form. A team on a seven-game winning streak looks unstoppable, but baseball is a sport where even the best teams lose 60 or more games per season and the worst teams win 50 or more. Streaks regress. The market already prices in recent form; your job is to assess whether the underlying performance supports the streak or whether the team has been getting lucky with sequencing and close-game wins.

Tenth: betting without a staking plan. This is the mistake that amplifies every other mistake on the list. Without defined unit sizes and a maximum exposure per game, every error costs more than it should. A bettor who makes mistakes three through nine but uses 1% flat staking will survive the season. A bettor who makes those same mistakes at 5% per bet will not.

A Quick Self-Assessment: How Many of These Apply to You

54% of online sports bettors placed at least one or two bets per week in 2025, yet the vast majority of them have never sat down to audit their own habits against a list like this. I recommend going through the ten points above with your last month of betting in mind. Be honest — not with me, but with yourself. Count how many apply.

If the answer is one or two, you are ahead of most recreational bettors and the fixes are minor adjustments rather than structural changes. If the answer is three to five, you have significant leaks that are costing you money every week, and addressing them should be your top priority before you invest any time in new models or strategies. If the answer is six or more, your approach needs a fundamental reset — and the best reset is to drop your unit size to the absolute minimum, start tracking every bet with the twelve fields described in our tracking guide, and rebuild your process from the ground up.

The good news is that every mistake on this list is fixable. None of them require advanced mathematics or expensive software. They require honesty about your current habits and the discipline to change the ones that are costing you. The baseball season is long enough — 2,430 games across six months — that a bettor who corrects even half of their mistakes in May will see the results by September.