A key element that can elevate a good team to greatness—or spark hope for fans of struggling franchises—is the performance of players who exceed preseason expectations. This article explores some of the best-kept secrets across Major League Baseball (MLB) teams in 2025. These players may include young talents who are maturing, or veterans defying typical performance patterns. It's important to note that this perspective is national; those who follow their teams through the 162-game schedule may not find any surprises. However, for fans eager to discover some of the sport's most underrated players, this analysis serves that purpose.

The New York Yankees have seen Fernando Cruz make a mark while recovering from right shoulder inflammation, boasting a 2.66 ERA in 21 games prior to his injury. Acquired in a trade involving Jose Trevino and the Cincinnati Reds in the offseason, Cruz stands out with an impressive 13.3 strikeouts per nine innings across 23.2 innings this season. Meanwhile, the Tampa Bay Rays' José Caballero, who led the American League with 44 stolen bases last year, has improved his base-stealing efficiency this season with 19 successful attempts out of 23. His OPS has risen from .630 in 2024 to a solid .735 in the ongoing campaign. In Toronto, Addison Barger, a sixth-round draft pick in 2018, has emerged as a potential long-term asset for the Blue Jays, hitting 11 doubles and achieving an .801 OPS through 37 games.

The Boston Red Sox's Brennan Bernardino, after a mixed 2024, has returned to form with a sharp 1.27 ERA over 27 appearances this season. Bryan Baker has been a bright spot for the Baltimore Orioles despite a rocky start to the season, offering a 2.88 ERA across the first 26 games. In Detroit, Will Vest has taken his performance to another level in 2025 with a 2.00 ERA and eight saves over 25 appearances, proving to be a valuable asset at just $1.4 million, with two years left before arbitration. The Cleveland Guardians’ Daniel Schneemann has filled in admirably for the injured Travis Bazzana, contributing seven home runs and a .779 OPS while showcasing defensive versatility.

For the Minnesota Twins, Louis Varland has had a remarkable season, registering a 2.73 ERA across a league-leading 29 appearances, a significant improvement over his previous career numbers. Kansas City Royals starter Noah Cameron has also impressed, posting a 1.05 ERA in his first four games after his promotion, complementing an already strong rotation. The Chicago White Sox's Mike Vasil has recorded a solid 2.10 ERA across 17 games, even with some concerns about his FIP. The Seattle Mariners have relied on Gabe Speier, who has excelled with a 2.01 ERA this season due to improved control, lowering his walk rate significantly. The Houston Astros' Bennett Sousa has emerged as a reliable left-handed option in the bullpen, pitching to a 2.50 ERA in limited appearances.

In Texas, Robert Garcia has proven to be a savvy acquisition from the Washington Nationals, compiling a 2.25 ERA in 28 games for the Rangers. José Soriano of the Los Angeles Angels, transitioning from a reliever to a starter, has found his footing with a 3.42 ERA since 2024, becoming a reliable fixture in the rotation. For the Athletics, Jacob Wilson has made headlines with a .345 average and an .883 OPS, positioning him as a strong contender for the AL Rookie of the Year Award despite defensive struggles. On the other hand, the Philadelphia Phillies have benefitted from Tanner Banks, whose performance has improved with a 3.28 FIP this season following an increased role in the bullpen.

The New York Mets have discovered an undervalued gem in Reed Garrett, who has posted a striking 0.73 ERA in his first 25 games after being claimed off waivers. The Washington Nationals' Cole Henry has also made headlines with a 2.14 ERA, providing a much-needed boost to a struggling bullpen. In the National League, Daysbel Hernández of the Atlanta Braves has shown potential despite commanding issues, with a solid 2.25 ERA. The Miami Marlins’ Valente Bellozo has kept pace with a 2.89 ERA through 28 innings, indicative of a positive development for the team. Chicago Cubs veteran Caleb Thielbar has achieved a remarkable 2.29 ERA in his first season with the franchise, a testament to his experience and adaptation.

Kyle Leahy has been instrumental for the St. Louis Cardinals, maintaining a 2.08 ERA to serve effectively as a setup man. The Milwaukee Brewers’ Abner Uribe has turned heads with an impressive 1.65 ERA, consistently performing in high-leverage situations. Lyon Richardson of the Cincinnati Reds has had a solid start to his season, allowing just two earned runs in 14 innings, and finding a role within the organization. The Pittsburgh Pirates’ Dennis Santana has emerged as a candidate for the All-Star team with a remarkable 1.48 ERA, generating interest as a valuable trade asset as the deadline approaches. In Los Angeles, Jack Dreyer has stepped up in the Dodgers' bullpen, matching the team’s playoff aspirations with a 2.97 ERA in 23 appearances.

San Diego Padres’ Gavin Sheets has rejuvenated his career with a switch to the team, showcasing substantial improvement as evidenced by his .269 batting average and 11 home runs. Lastly, Randy Rodríguez of the San Francisco Giants has returned as a dominant bullpen presence with a minuscule 0.70 ERA, while Shelby Miller has been a consistent performer for the Arizona Diamondbacks with a 1.99 ERA. In perhaps a flicker of promise for the Colorado Rockies, Jordan Beck has begun to find his stride with eight home runs and an .810 OPS in his second season. Collectively, these players reflect the depth of talent in the league and provide compelling narratives as the season progresses.