The 10 Most Disappointing Players of the 2026 MLB Season

The 2026 season is winding down, with less than three weeks until the calendar turns to October and the stakes heighten as postseason baseball gets into full swing. As we reflect on the season, there have been plenty of breakout performances across the majors. Unfortunately, there were also numerous players who vastly underperformed their expectations.

Read more Three Bold Predictions for Ben Shelton and Frances Tiafoe’s All-American U.S. Open Semifinal

We’re going to look at the league’s 10 most disappointing players this season, highlighting past All-Stars who have just about run out of time to turn around difficult campaigns.

10. Paul Skenes, Pirates SP

By most pitchers’ standards, Skenes is having a decent year. By Skenes’s standards, the 2026 campaign has been a rough one. He owns a 3.83 ERA and has surrendered a career-high 15 home runs across 155 2/3 innings, while striking out 181 batters and walking 45, also a career high. After consecutive seasons with a sub-2.00 ERA to start his career, Skenes was the favorite to win the NL Cy Young entering the year, but he finds himself out of that conversation entirely as the season winds down. He had some issues with velocity throughout the season, and an adjusted arm angle on the mound made his pitches less difficult to hit, resulting in some disappointing outings for the 24-year-old. It was a down year for Skenes, though the Pirates likely don’t have much concern about his ability to turn things around in ’27.

9. Freddy Peralta, Mets/Rays SP

The Mets paid a hefty price to pry Peralta from the Brewers in the offseason, sending their top two prospects to Milwaukee in Brandon Sproat and Jett Williams. Less than a full season after making that trade, New York shipped the struggling right-hander to the Rays for three prospects. Peralta had minimal success in a Mets uniform, though he’s begun to turn things around in Tampa, at least marginally. Overall, he owns a 4.82 ERA with 142 strikeouts against 55 walks and has surrendered 23 home runs in 153 innings. Set to hit free agency in the offseason, Peralta would’ve benefited massively from another strong campaign, but his struggles make him one of MLB’s biggest uncertainties hitting the open market in the winter.

8. Marcus Semien, Mets 2B

Semien was acquired during the offseason in a swap for Brandon Nimmo, but the veteran second baseman has been dreadful for the Mets. Semien owns a career-worst .629 OPS on the year and has some pretty concerning underlying metrics at the plate. He’s in the 10th percentile in bat speed, 21st percentile in hard-hit percentage and 13th percentile in average exit velocity––in other words, he’s not hitting the ball hard regularly and isn’t generating much power with his swing.

At 35 years old (soon to be 36), Semien has been regressing over the last few years, and it’s unlikely his play improves throughout the final two years of his contract, wuring which he’s owed $46 million. What’s most concerning is his rapid defensive decline. Semien has been one of MLB’s worst defensive infielders this season. He has -6 outs above average, which ranks 230th of 264 among qualified players.

7. Willy Adames, Giants SS

Adames has struggled a bit at the plate, though he’s still hit 21 home runs on the year. He owns the lowest walk rate of his career (7.3%) and is striking out in 27.5% of his plate appearances, his highest rate since 2021. It’s defensively that he’s been truly disappointing, however. No player in MLB has a fewer outs above average than Adames (-17), nor runs prevented (-13), and he ranks third in all of baseball with 18 errors on the year.

Adames has been dealing with a lingering back injury throughout much of the campaign, which has likely impacted his performance, but he’s been quite disappointing this season, especially for a player with a back-loaded contract that’ll pay him over $31 million annually through the 2031 season.

6. Trea Turner, Phillies SS

Turner had a brilliant season in 2025, but he’s been dismal in ‘26. A contact hitter by trade, Turner is batting just .241 this season and has an OBP below .300 for the first time in his career. The veteran infielder is at his best when he’s getting on base and using his speed to steal bases. That hasn’t been happening this year, as he’s swiped just 18 bags in 140 games.

He’s also struggled defensively, owning -7 outs above average, -5 runs prevented at shortstop and an MLB-leading 20 errors. For a player earning over $27 million annually, Turner’s production this season has been far below his expectations, though the Phillies remain competitive in spite of that.

Read more 2026 MLB Trade Deadline Superlatives, Five Weeks Later

5. Edwin Diaz, Dodgers RP

dfdDiaz has endured a tumultuous first season in Los Angeles. Injuries have largely derailed his campaign, but when he’s been on the mound the results have not been pretty. In 16 appearances, Diaz owns an unsightly 11.85 ERA, having surrendered three home runs, walked 10 batters and struck out 19 in 13 2/3 innings. He owns a career low -1.3 bWAR and returned to the IL in mid-August after a string of disastrous outings in which he surrendered six earned runs across his last 2 2/3 innings. Making $23 million per season, Diaz is MLB’s highest-paid relief pitcher, yet he’s failed to provide the expected impact to an already-formidable Dodgers squad.

4. Jarren Duran, Red Sox OF

After a dominant 2024 season and a solid ‘25, Duran has been dreadful this year for the Red Sox. He owns a .624 OPS across 136 games this year, despite hitting 20 home runs––just one shy of his career high. Duran has used his speed to rack up high extra-base hit numbers over the last few years. He led MLB with 14 triples in 2024, when he had 83 extra-base hits, and racked up 70 last year. This season, that hasn’t been the case. He’s hit just 15 doubles and four triples on the year, and his stolen base numbers are down across the board.

Duran’s eye at the plate has been particularly woeful this year. He’s walking in a career-low 6.4% of his plate appearances and he ranks in the 19th percentile for chase percentage (34.9%) and fifth percentile for whiff rate (33.9%).

3. Kyle Tucker, Dodgers OF

The Dodgers’ big-money acquisition has had a brutal first season in Los Angeles. Tucker had never previously posted an OPS below .800 in his career, but he’s down to a woeful .671 OPS in ‘26, well below league average. Tucker has 13 home runs, 60 RBIs and has a career-high 99 strikeouts in 137 games. In addition to his struggles at the plate, Tucker has been abysmal defensively in right field. He’s recorded -9 outs above average, which ranks 253rd among 265 qualified players, and his -8 runs prevented this season rank 254th. Those are putrid numbers for a player earning $60 million annually, and he’s regressed massively in just about every statistical category.

2. Vladimir Guerrero Jr., Blue Jays 1B

Guerrero has not looked like the same player who earned himself a 14-year, $500 million contract extension from the Blue Jays prior to last season. After racking up 22.9 bWAR over the previous five years, Guerrero has generated just 1.0 bWAR across 131 games in 2026, and his OPS is down to a career low of .682. He hit 159 home runs from 2021 to ‘25, but has gone yard just eight times during the ‘26 season. Despite his lack of power at the plate this year, Guerrero has a career-best 12.7% strikeout rate, which ranks in the 92nd percentile league-wide, though he’s still not seeing the desired results despite regularly putting the ball in play.

1. Cal Raleigh, Mariners C

After his record-breaking season in 2025, Raleigh hasn’t been able to get things going at the plate this year. He hit 60 home runs and recorded 125 RBIs in 159 games last year, but has just 21 home runs and 59 RBIs in 110 games in ‘26. Raleigh has struggled at keeping up with fastballs this season, resulting in a career-high 31% strikeout rate, which ranks as the ninth-highest in MLB. He picked it up a bit in August, when he hit nine of his 21 home runs on the year, though his batting average remained below .200 for the month.

Raleigh’s downfall from MVP candidate to one of the most disappointing players in all of MLB has been remarkable. Few players in league history have experienced the type of drop-off in production that Raleigh has– his impressive .948 OPS from last season has plunged more than 250 points in ’26, to a sub-par .672. During the lowest point of his first-half slump, Raleigh had a .560 OPS through 57 games. That’s largely the result of his reduced slugging percentage this year (.376), which is more than 200 points below his .589 mark from ’25.

This article was originally published on www.si.com as The 10 Most Disappointing Players of the 2026 MLB Season.

Copyright ABG-SI LLC. SPORTS ILLUSTRATED is a registered trademark of ABG-SI LLC. All Rights Reserved.

Read more The Clippers Are Fumbling Another Situation. This Time, It Involves Chris Paul.