The 2025 season was a step in the right direction for the Red Sox, as they won 89 games, took the second AL Wild Card spot and lost in the AL Wild Card Series in three games to the Yankees.
Following three straight seasons in which the Red Sox missed the playoffs and didn’t finish above .500, the club is trending toward reestablishing itself as an annual contender. Even with Rafael Devers traded last year and much to be determined during this offseason — third baseman Alex Bregman is a prominent free agent — there is no shortage of potential impact players on the Red Sox roster. Some of those could be in position to have a much greater impact on the 2026 team than they did in 2025.
For the sake of this exercise, we’re looking beyond the obvious names like Garrett Crochet, Roman Anthony, Trevor Story, Ceddanne Rafaela, etc. and taking a look at five players poised to be X-factors for the Red Sox in 2026.
Injuries have unfortunately derailed most of the last two seasons for Casas, who played a combined 92 games from 2024-25. This came after a strong 2023 rookie season, when Casas posted an .856 OPS with 24 home runs in 132 games while finishing third in AL Rookie of the Year voting. Casas was productive in 63 games in 2024 (.800 OPS and 13 homers) but struggled in 29 games last season (.580 OPS).
Here’s the good news: Casas will only be 26 on Opening Day next year and has been plenty effective outside of 29 injury-riddled games last season. If Casas remains healthy, there’s every reason to believe that he can be a force in the middle of the Red Sox lineup. With strong plate discipline and pop — he does swing and miss a good amount — Casas has a chance to give Boston a middle-of-the-order threat in 2026.
Mayer didn’t quite light the league on fire like his fellow rookie Anthony, but he still held his own with a .674 OPS in 44 games. A right wrist injury ended his season in late July, but successful surgery has Mayer on track to be ready for Opening Day in 2026. The No. 4 overall pick from the 2021 Draft has a chance to take a huge step forward for the Red Sox in ‘26.
There’s plenty to like in Mayer’s profile. In his first 44 MLB games, Mayer had a 51.7 percent hard-hit rate (percentage of balls hit 95-plus mph) and showed an average-or-better barrel rate, bat speed and average exit velocity. Along with three Outs Above Average on defense, Mayer showed an ability to make an impact on both sides of the ball. Yes, Mayer will need to cut down on the strikeouts (30.1 percent in 2025) and take a few more walks (5.9 percent), but those numbers were much better during his time in the Minors, where he boasted a career 23.0 percent strikeout rate and an 11.7 percent walk rate.
Yet another Red Sox rookie who made a big impression, Early was downright dominant in his first four MLB starts. In 19 1/3 innings, Early allowed just six runs (2.33 ERA) while striking out 29 batters and walking four. That included 11 strikeouts in five scoreless innings in his MLB debut against the A’s in West Sacramento on Sept. 9.
Early, who was drafted in the fifth round of the 2023 Draft out of the University of Virginia, clearly established himself as a member for the 2026 rotation, likely slotting behind Crochet, Brayan Bello and any possible free-agent signing or trade acquisition. With a strong six-pitch mix and an ability to command the baseball, Early could potentially be a mid-rotation starter for the Red Sox as early as next year.
Kristian Campbell, INF/OF
Campbell began his season as one of the most talked-about players in the sport. MLB Pipeline’s No. 7 prospect entering the season, Campbell made the Red Sox Opening Day roster and signed a long-term extension worth $60 million that will keep him in Boston through the 2032 season. Campbell was excellent through the end of April, posting a .301/.407/.495 slash line in 123 plate appearances.
Unfortunately, Campbell struggled to the tune of a .159/.243/.222 clip across his next 38 games and was optioned to the Minors on June 20, where he spent the rest of the season. On the bright side, Campbell still showed what he could do in his first month in the Majors and will enter next season as a 23-year-old with strong prospect pedigree. Perhaps no Red Sox player has a wider range of outcomes, but Campbell progressing to becoming a staple in Boston would be huge for the organization.
Sandoval signed a two-year, $18.25 million contract with the Red Sox last offseason with the expectation that he would miss most if not all of the first season after undergoing Tommy John surgery in June 2024. Sandoval ultimately did not throw a pitch for Boston last season, but the left-hander is expected to be ready to contribute in 2026.
What version of Sandoval the Red Sox get post-surgery remains to be seen. He’s still just 29 years old and was an effective member of the Angels rotation for several years, with his best year coming in 2022, when Sandoval had a 2.91 ERA and 3.7 Wins Above Replacement (FanGraphs) in 148 2/3 innings. His numbers slid back in the following two seasons before surgery, but there’s enough of a track record to think Sandoval could be a solid starter for the Red Sox in 2026.
