There’s no doubt the Cubs exceeded expectations this year. Their over/under win total was set at 86.5 at BetMGM before the season, and the North Siders went on to win 92 games in the regular season. They then beat the San Diego Padres in the Wild Card Round. 

Although the Cubs fell to the Milwaukee Brewers in five games in the National League Division Series, the 2025 season was a step forward for a franchise looking for another World Series title. 

So, let’s break down this past season and determine which Cubs player was the biggest surprise breakout. 

Pete Crow-Armstrong didn’t post the best numbers during his rookie campaign in 2024. He only hit .237 with 10 home runs, 47 RBI, and 27 stolen bases across 123 games. But we saw Crow-Armstrong start to take off offensively in the second half of that season, hitting .284 over his final 52 games. 

That strong stretch toward the end of his rookie year carried over into 2025, where Crow-Armstrong fully broke out. He hit .247 with 31 home runs, 95 RBI, and 35 stolen bases across 157 games.

Even though the second half of the season was rough for Crow-Armstrong, he really showed his potential. His 6.0 WAR ranked second on the team, and he became just the second player in Cubs history to have a 30-30 season -- joining Sammy Sosa. 

Michael Busch was arguably the best Cubs hitter throughout the 2025 season. He hit .261 with 34 home runs, 25 doubles, and 90 RBI across 155 games. Those numbers were all career-bests for the 27-year-old first baseman. 

It’s refreshing to see Busch really take off offensively because the potential was always there. He hit .248 with 21 home runs and 65 RBI in his first season with the team in 2024, and then fully broke out this past year. 

Busch also emerged as one of the best-hitting first basemen in all of baseball during his 2025 breakout campaign. His 34 home runs ranked third, his 90 RBI ranked fifth, his .866 OPS ranked third, and his .523 SLG ranked second among all first basemen. 

This last breakout spot was between Cade Horton and Seiya Suzuki. But Horton felt deserving of being on this list after posting the numbers he did in the second half of the season. 

The rookie had a 1.03 ERA and 54 strikeouts across his final 12 starts. Horton allowed one run or fewer in 11 of those 12 outings, and the best game of his short career came in a start against the Los Angeles Angels on August 23. In that game, the right-hander threw six shutout innings with seven strikeouts. 

Horton was easily the best pitcher in the second half of the season. He led all starters in the second half with a 1.03 ERA and should be the favorite to win the NL Rookie of the Year Award in a few weeks. 

All three players were surprise breakouts for the Cubs during the 2025 season. However, the biggest surprise breakout belongs to Crow-Armstrong. 

His second half of the season might have been rough, but no one expected the 23-year-old to hit over 30 home runs this past year. He also became just the eighth player in MLB history to have a 30-home run, 30-stolen base season at age 23 or younger. That’s some rare company to join.