Why Underdogs?

In sports betting, most people chase winners. But value-driven bettors know that underdogs often hold the key to long-term profit. The trick isn’t to bet against the odds. It’s to recognize when the odds are wrong.

Underdogs don’t just represent high-risk gambles. When you understand how sportsbooks set lines and how the public reacts, you can spot hidden value where others see weakness. This isn’t about betting on miracles. It’s about betting on misjudged probabilities.

What Is an Underdog Bet?

An underdog is any team or individual that oddsmakers believe is more likely to lose. In betting terms:

• A +250 underdog means a $100 bet wins $250 (plus your stake back).

• A -300 favorite requires a $300 wager to win $100.

Although underdogs win less often, their bigger payouts mean you don’t need to win as frequently to be profitable. A +250 underdog only needs to win about 29% of the time to break even.

This is where expected value (EV) comes in. EV refers to the average return of a bet if you placed it over and over again. If your research shows an underdog has a 35% chance of winning, and the sportsbook line implies 29%, you’ve found a +EV bet. This math, more than emotion or loyalty, drives smart betting.

When to Bet the Underdog

Betting underdogs successfully requires context, not luck. Here are four of the strongest indicators that an underdog bet makes sense:

1. Market Overreactions

The betting public tends to overreact to blowout wins, buzzy narratives, or recent losses. Sportsbooks adjust accordingly, not just to balance risk but to take advantage of public sentiment.

In Game 3 of the 2023 WNBA Finals, the New York Liberty defeated the Las Vegas Aces after a lopsided loss in Game 2. According to closing odds reported by multiple sportsbooks, the Aces were favored by 5.5 points, despite both teams having split the first two games. Sharp bettors noticed the line had shifted too far toward Las Vegas and jumped on the Liberty, who won outright.

A similar pattern unfolded in Week 3 of the 2023 NFL season when the Arizona Cardinals, coming off two losses, were 12.5-point underdogs against the heavily favored Dallas Cowboys. The public backed Dallas heavily, but Arizona pulled off a decisive win. It was a classic example of recency bias, where bettors overweight recent outcomes and undervalue long-term fundamentals.

2. Defensive Strength and Game Control

Underdogs with strong defenses or the ability to dictate pace frequently cover or pull off upsets.

In March Madness 2023, Florida Atlantic University reached the Final Four as a No. 9 seed. Their ball control, efficient defense, and deliberate tempo helped neutralize higher-seeded teams. They covered the spread in four of five games.

In the 2023 NCAA Women’s Sweet 16, the Miami Hurricanes upset No. 1 seed Indiana with aggressive perimeter defense and control of tempo. Despite entering as 7-point underdogs, Miami won 70–68. Slower pace and limited possessions compress the margin for error and amplify the value of efficient defense, especially for underdogs.

Controlling the tempo matters. In the NFL, for instance, underdogs that dominate time of possession and limit big plays often outperform expectations. Bettors who study pace, efficiency metrics, and turnover margins can spot underdogs poised to punch above their weight.

3. Star Players Returning from Injury

Injury news can dramatically swing betting lines, but sometimes the market overcorrects or reacts too slowly to positive updates.

In Week 5 of the 2023 NFL season, Joe Burrow returned to near-full strength for the Cincinnati Bengals after a slow start due to a calf injury. The Bengals, underdogs by 3 points against the Arizona Cardinals, were undervalued by the market. Burrow threw for three touchdowns and the Bengals covered easily, 34–20.

In the WNBA, when the Chicago Sky welcomed back star Kahleah Copper after a midseason absence, early bettors took advantage of soft lines before sportsbooks fully adjusted. Injury-return situations often lag behind public perception, especially when the returning player’s status is ambiguous.

This also applies to individual sports like tennis, where players returning from injury, especially unseeded ones, are often mispriced. Bettors who follow injury reports and team beat writers can gain a significant edge here.

4. Overvalued Favorites and Fan Bias

Some teams are over bet simply because they’re popular. That pushes their odds below true value and boosts the value of their opponents.

The Dallas Cowboys, Los Angeles Lakers, and UConn Huskies women’s basketball team all draw public money consistently, even when form is shaky. These teams carry inflated lines because sportsbooks know fans will back them regardless of value.

In Major League Baseball, the New York Yankees and Los Angeles Dodgers frequently open as large favorites, especially at home. But when their opponent has a starting pitcher with strong metrics like a high strikeout rate or low WHIP, sharp bettors often fade the public and grab the plus-money underdog.

This is a psychological trap known as fandom bias. Bettors back teams they know or support emotionally while ignoring more objective performance indicators. Recognizing this allows savvy bettors to step away from the hype and toward value.

Sharp Bettors, EV, and Public Action

Two key concepts to remember:

• Sharp Bettors use models, matchup data, injury info, and market timing to find profitable opportunities. They often bet against public sentiment.

• Expected Value (EV) is the math behind winning bets. A +300 underdog only needs to win 25% of the time to be profitable. If your research indicates a higher probability, you’ve found long-term edge.

Sharp bettors don’t chase underdogs for thrill. They bet them when the odds misprice the reality.

Real-World Data Snapshot

This chart shows approximate win rates of underdogs against the spread.

Verified data confirms underdogs can consistently provide betting value:

• NFL underdogs covered the spread in 52.6% of games between 2018 and 2023, according to Action Network. Above is ATS (Against The Spread) Win Rates

• In 2023 March Madness, underdogs covered in 60% of first-round games and won 10 of 32 outright. [Source: NCAA Game Logs]

• In MLB, underdogs of +200 or greater won at a 28.9% rate in 2022, according to Sports Insights, which is enough to turn profit if selectively bet.

  
  

These stats prove that with the right discipline and selection, underdogs can outperform public perception.

Final Thoughts: The Smart Way to Back the Dog

Betting on underdogs isn’t about gambling on miracles. It’s about uncovering opportunity where others see risk. When public overreaction, injury misreads, or fandom bias skew the odds, you can step in with clarity.

Start by tracking line movement, analyzing tempo, studying matchups, and monitoring injury updates. Use tools like closing line value and implied win probability. Be selective, be informed, and don’t bet just to be contrarian. Bet because the numbers back it.

If you're ready to bet smarter, underdogs offer more than long shots. They offer long-term returns.