The Mariners have MLB's top bullpen

MLB Bullpen Betting Trends: Mariners Boast Top 'Pen

Every baseball fan and bettor knows the feeling. When the manager walks out onto the grass and raises an arm — the dreaded call to the bullpen. For some teams, a late-game lead means the contest is already won. But for the league’s worst bullpens, that call for a reliever often spells disaster.

Bad MLB bullpens are hard to watch. But we’re making them profitable. Below, we’ve broken down the best and worst bullpens in baseball and how you can capitalize on them to make some betting profit.

We’ve got data from the first few weeks of the 2023 season below and we’ll update this page throughout the year until the World Series:

2023 MLB Worst Bullpen Betting Trends

Baseball’s Worst Bullpens In 2023
Team7-9th Inning Team ERA7-9th ERA When Winning7-9th ERA Up 1 Run
Washington Nationals5.536.125.00
Colorado Rockies5.276.787.41
Chicago White Sox5.246.296.35
St. Louis Cardinals5.235.766.07
Los Angeles Angels5.034.405.82

Data courtesy of Odds Shark’s database as of August 31st, 2023

A horrendous 6.78 late-game ERA when leading by a single ensures that no lead is safe for the Rockies. If you see Colorado up a run in the eighth inning, consider a live-fade due to its awful 'pen.

The Cardinals are one of baseball's most disappointing teams this season, and their bullpen is largely responsible. St. Louis' lineup actually ranks ninth in OPS this year, yet the team is 20 games below .500. Relief pitching should be at the top of the Cards' offseason shopping list.

2023 MLB Best Bullpen Betting Trends

Baseball’s Best Bullpens In 2023
Team7-9th Inning Team ERA7-9th ERA When Winning7-9th ERA Up 1 Run
Seattle Mariners3.453.202.70
Toronto Blue Jays3.533.223.68
New York Yankees3.594.501.97
Tampa Bay Rays3.663.754.91
Baltimore Orioles3.733.472.92

Data courtesy of Odds Shark’s database as of August 31st, 2023

There aren’t many surprises among the dominant bullpens so far this season, as many of these top units were the best on paper entering the year.

But, one team actually sold from their bullpen depth in the offseason and still has one of the league's best reliever units: the Seattle Mariners. The Mariners have caught lightning in a bottle in recent weeks and suddenly lead the AL West. The bullpen has kept the team afloat all season and is now leading a playoff push.

Even after trading Erik Swanson in the offseason and Paul Sewald at the deadline, the Mariners 'pen has been carved, and that's in part thanks to the rotation. Luis Castillo, George Kirby, Logan Gilbert and Bryce Miller are averaging close to six innings pitched per start this season, providing Seattle's 'pen with ample rest, enabling their standout performance so far.

Check below for some tips on how to use this bullpen data to inform your bets, but one of the main things to note with these best bullpens is to not expect a comeback if you’re betting against them.

If you’re looking for more MLB betting resources, check out Odds Shark’s MLB Betting Hub as well as our MLB computer picks page.

How To Profit Off Bad Bullpens

The best way to profit off these shaky bullpens is by tracking games and keeping an eye out for live-betting situations.

If these bad late-game pitching squads have a one- or two-run lead heading into the final few frames, it’s worth sprinkling some cash on the opposition for a hefty underdog payout! All of the top baseball books have live-betting options, so sign up and watch out for a leaky bullpen getting the lead.

Bad Bullpen? Bet The OVER

Another way to capitalize on bad bullpens and shaky late-game pitching is by betting the OVER.

The Diamondbacks, who were the second-worst ’pen in baseball in 2021 per 7-9th inning ERA, hit the OVER at 57.4 percent that year, tops in the league. While OVER/UNDER betting in baseball often bakes in opponent offenses and starting pitching matchups, the late-game pitching is often forgotten. 

How To Bet On MLB Baseball

There are three main ways to bet on MLB, in the form of moneyline betting, runline betting or total runs. Moneyline betting is simple, where you just choose the winner of a game. Total runs betting is where you bet on whether the total runs scored in a game will go OVER or UNDER a preset total.

Like most spread bets, for an MLB runline you’re betting that the favorite (denoted by a minus sign) will win by a set number of runs (usually 1.5), or that the underdog (denoted by a plus) will win outright or lose by less than a set number of runs. At any sportsbook, you’ll notice MLB runline spread odds are listed like this:

  • Toronto Blue Jays -1.5
  • Minnesota Twins +1.5

In this example, the Blue Jays are 1.5-run favorites. If you believe that the Jays will win by more than 1.5 runs, you can bet on them to win. If you think the Twins will win, or lose by less than 1.5 runs, you should bet on them!

Check out our odds calculator to see how much you’d win based on the odds and amount wagered, as well as the implied probability of all odds.

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