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2025 MLB Season Preview: Sleeper AL & NL Teams Who Could Make The Postseason

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By
Colin Lynch
Author photo
Colin Lynch Sports Editor

Colin Lynch covers the NFL, MLB and WNBA for Heavy.com, with a focus on the New England Patriots. His sports coverage has been featured on The Sports Daily and Basketball Insiders, as well as FanSided's Chowder & Champions. A New Hampshire native and former D1 baseball player at St. John's University, Colin was drafted by the San Diego Padres in 2008 and enjoyed a four-year professional baseball career.

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Published27 Feb 2025

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2025 MLB Season Preview: Sleeper AL & NL Teams Who Could Make The Postseason

2025 MLB Season Preview: Sleeper AL & NL Teams Who Could Make the Postseason

“Wait until next year.”

It’s the refrain of every team that fell just short, every club left watching the postseason from home. But in Major League Baseball, next year doesn’t arrive the same way for everyone. Some teams are in full rebuild mode, playing the long game for future contention. Others? They are just one key acquisition, one bounce-back season, or one stroke of luck away from October baseball.

As the 2025 season looms, a handful of teams stand at the edge of that turning point, ready to take a step forward. Here are six teams—three from the American League, three from the National League—who could be this year’s biggest surprises.

Seattle Mariners: Can the Bats Catch Up to the Arms?

The Mariners have spent the past two seasons watching their elite pitching staff carry the weight, only to fall just short in the Wild Card chase. In 2024, they finished two games back, their lineup unable to support a rotation that led the Majors in ERA, opponents’ batting average, and strikeout-to-walk ratio.

Seattle’s front office knows the window is now. With every starter under team control through 2027, they must address an offense that ranked 21st in runs scored and 22nd in OPS.

Biggest Obstacle: Will the lineup be able to match how good their pitching could be?

Boston Red Sox: A Team Poised for a Leap?

Boston has talent. They also have questions.

In 2024, the Red Sox rotation lacked a frontline ace beyond Tanner Houck (3.12 ERA). Their bullpen struggled, posting the 24th-ranked ERA (4.39) and blowing 31 saves, the second-most in baseball. This offseason, they added bonafide ace Garrett Crochet. 

They also added Walker Buehler to help headline the staff, and a healthy Trevor Story will bring much-needed stability to the infield. The farm system could provide an extra spark, with Marcelo Mayer and Roman Anthony knocking on the door with Kristian Campbell. The addition of Alex Bregman may be the bat that makes this offense one of the most dynamic in baseball.

If all the pieces come together, the Red Sox could be this year’s team that jumps from .500 to a real playoff threat.

Biggest Obstacle: Can their young arms handle a full workload?

Texas Rangers: A World Series Comeback?

After winning it all in 2023, the Rangers stumbled to 78-84 last year, undone by injuries and bullpen struggles.

But 2025 offers hope. Jacob deGrom is set to return from Tommy John surgery. Corey Seager is healthy after multiple injuries limited him in 2024. Add in newcomers Joc Pederson and Jake Burger, plus a full season of Wyatt Langford, and Texas’ lineup could be a force again.

Biggest Obstacle: Their bullpen. It ranked 26th in MLB last year (4.41 ERA), and they still lack a defined closer.

Chicago Cubs: Closer Than They Seem?

Back-to-back 83-win seasons don’t scream breakout team, but the Cubs’ expected win total (based on run differential) was 90 in 2023 and 88 in 2024. That suggests Chicago is on the verge of a real leap.

The addition of Kyle Tucker brings an elite bat, and their rotation remains solid. If they shore up the bullpen—already a focus with Ryan Pressly reportedly on the way—the Cubs could be this year’s version of the 2023 Diamondbacks. They also added Justin Turner to help solidify the lineup.

Biggest Obstacle: Late-game struggles. Chicago lost 12 games they led after the seventh inning in 2024.

Pittsburgh Pirates: The Dark Horse of the NL Central?

If the Pirates surprise the baseball world, it will be because of Paul Skenes and Jared Jones. These two young fireballers could headline one of the best one-two punches in the National League. There are also Mitch Keller and Bailey Falter, who will round out a dynamic young starting rotation.

Then there’s Oneil Cruz—a potential Elly De La Cruz-style breakout waiting to happen. If he stays healthy, Pittsburgh suddenly has a lineup that can compete with anyone.

Biggest Obstacle: Depth. Unlike the Cubs and Brewers, the Pirates lack proven veteran contributors. If injuries hit, they could struggle to keep pace.

Arizona Diamondbacks: Can They Recapture 2023 Magic?

Last year, the D-backs came within inches of defending their NL pennant but fell short of the postseason. The biggest issue? A rotation that fell apart behind Zac Gallen.

Jordan Montgomery, their big 2024 free-agent signing, posted a 6.23 ERA, and closer Paul Sewald regressed. Now, Arizona faces a new challenge— losing Christian Walker and Joc Pederson.

But Corbin Carroll’s return to MVP form could change everything. If they re-sign Walker or land another power bat, the D-backs could be a Wild Card contender once again.

Biggest Obstacle: Can they replace the power lost in free agency?

A’s in the Playoffs? Believe It.

It sounds unthinkable, but the A’s could be baseball’s Cinderella story in 2025.

After a miserable few years, Oakland (now Sacramento) showed promise in the second half of 2024, going 39-37 after July 1. Their offense, powered by Brent Rooker (39 HRs) and Zack Gelof, finished eighth in MLB in home runs (196).

They’ve also added Luis Severino and Jeffrey Springs to solidify the rotation. With just a little regression from teams like the Yankees or Astros, the A’s might be the surprise of the season. With Micahel Otanez and Mason Miller at the back end of the bullpen, the A’s might have the best one-team reliever combo in baseball.

Biggest Obstacle: Are they still a year away from truly contending?

Final Thoughts: Who Will Be This Year’s Surprise Playoff Team?

Every season, at least one team defies expectations. In 2023, it was the Diamondbacks. In 2024, it was the Orioles winning 101 games. The O’s will regret not adding more starting pitching in a super competitive AL East.

This year? The Mariners, Red Sox, and Rangers have the talent to surprise in the AL, while the Cubs, Pirates, and D-backs are poised for a jump in the NL.

One thing is certain: the road to October always has a few unexpected twists.