Part of what elevates a good team to greatness, or offers hope to fans of struggling franchises, is the emergence of players who exceed preseason expectations. In this analysis, we explore some of the best-kept secrets for each MLB team as of the 2025 season. These players may include promising young talents blossoming into key contributors or veterans significantly outperforming their career norms. This overview is written from a national perspective, offering insights that even the most devoted fans may find enlightening.

For the New York Yankees, Fernando Cruz has emerged as a notable asset, boasting an impressive 2.66 ERA in 21 games before being sidelined by right shoulder inflammation. Acquired in the offseason trade that saw José Trevino move to the Cincinnati Reds, Cruz has an impressive strikeout rate of 13.3 K/9 across 23.2 innings pitched in his debut season with the Yankees. Over in Tampa Bay, José Caballero continues to showcase his speed, having stolen 44 bases last year. While he struggled with a league-worst 16 caught stealing, his success rate has improved this season, with 19 successful steals out of 23 attempts, alongside a rising OPS from .630 to .735.

Meanwhile, Toronto Blue Jays' Addison Barger, a sixth-round pick from the 2018 draft, is establishing himself as a long-term prospect, contributing 11 doubles, an .801 OPS, and a 1.2 WAR over 37 games this season. For the Boston Red Sox, Brennan Bernardino has turned in a stellar performance out of the bullpen, achieving a 1.27 ERA and a 3.34 FIP over 27 games, rebounding from a challenging 2024 campaign. Bryan Baker has also stood out for the Baltimore Orioles following a tumultuous first two months, posting a 2.88 ERA across 26 outings.

The Detroit Tigers' Will Vest has been even more effective in 2025, recording a 2.00 ERA and eight saves through 25 appearances. The Cleveland Guardians have a promising option in Daniel Schneemann, who has filled in admirably since Andrés Giménez's departure, hitting seven home runs with a .779 OPS while demonstrating defensive versatility. In Minnesota, Louis Varland stands out with a 2.73 ERA and 3.16 FIP across a league-leading 29 appearances, marking a significant improvement from prior seasons.

The Kansas City Royals have bolstered their already strong rotation with Noah Cameron, a seventh-round draft pick in 2021, who debuted with a remarkable 1.05 ERA in four starts after his promotion in late April. For the Chicago White Sox, Mike Vasil's numbers are noteworthy despite concerns about his 4.54 FIP. His 2.10 ERA in 17 games has certainly earned him recognition, albeit with some caution regarding sustainability.

Seattle Mariners' Gabe Speier has transformed his performance considerably, achieving a 2.01 ERA and demonstrating remarkable control improvements compared to past seasons. The Houston Astros have also seen promise from Bennett Sousa, contributing with a 2.50 ERA in 15 games this season. The Texas Rangers made an astute acquisition by bringing in Robert Garcia, who has thus far lived up to expectations with a 2.25 ERA over 28 games.

José Soriano of the Los Angeles Angels has made a notable transition from bullpen to quality starter, illustrating growth with a 3.42 ERA since 2024. The Oakland Athletics’ Jacob Wilson is making waves with a .345 batting average and an .883 OPS, positioning himself as a potential frontrunner for AL Rookie of the Year. Tanner Banks has stepped up for the Philadelphia Phillies, contributing a solid 3.28 FIP in 25 games as a left-handed reliever amid a veteran-laden roster.

Reed Garrett is another player making headlines for the New York Mets, having turned a rocky start into an impressive 0.73 ERA over 25 games this season. The Washington Nationals have found reliability in Cole Henry, showcasing a 2.14 ERA through 18 games, which would be a significant asset for a bullpen that is currently struggling. In Atlanta, Daysbel Hernández is demonstrating potential with a 2.25 ERA, albeit needing to improve control to solidify his spot in the bullpen.

Valente Bellozo has provided some positive news for the Miami Marlins with a 2.89 ERA over 28 innings, reflecting potential growth and contribution to a struggling team. Caleb Thielbar, at 38 years of age, has shown resilience for the Chicago Cubs, achieving a 2.29 ERA in his first season with the club. Kyle Leahy is another player contributing significantly to the St. Louis Cardinals, posting a 2.08 ERA over 30.1 innings pitched.

Abner Uribe offers a promising addition to the Milwaukee Brewers' bullpen, with a 1.65 ERA in 28 appearances, continuing the club's tradition of cultivating effective relievers. Lyon Richardson is raising eyebrows for the Cincinnati Reds, allowing only two earned runs across 14 innings this season, although his advanced statistics may indicate a potential regression. The Pittsburgh Pirates' Dennis Santana has emerged as a standout reliever with a 1.48 ERA, positioning himself as a potential All-Star candidate and a valuable trade asset as the season progresses.

The Los Angeles Dodgers have been kept afloat by Jack Dreyer, who has stepped in admirably during an injury-plagued season, recording a 2.97 ERA through 23 games. Lastly, Gavin Sheets of the San Diego Padres is enjoying a rejuvenation with his new team, hitting .269 with 11 home runs, a considerable improvement from past seasons during his tenure with the White Sox. The San Francisco Giants’ Randy Rodríguez has experienced a revival, owning a 0.70 ERA in 24 appearances this season after a challenging rookie year.

Lastly, Shelby Miller of the Arizona Diamondbacks has established himself as a dominant force with a 1.99 ERA in 23 games, while Jordan Beck has provided some bright spots for the Colorado Rockies, hitting eight home runs in his second MLB season despite the team's struggles.