10 MLB Stars With the Most to Prove Before the 2026 Playoffs
GOATIFYSeptember is when reputations get rewritten in Major League Baseball. A strong first five months can be forgotten after a bad stretch, while a difficult season can suddenly look much better if a player delivers when the postseason race tightens.
That pressure is especially intense in 2026 because so many contenders are relying on major names who either missed significant time, have performed below their usual standards or are trying to prove they can be trusted in October. Some are former MVP candidates. Some are established postseason arms. Others are young stars whose biggest challenge is simply staying healthy long enough to matter.
The list below is not about identifying the worst seasons. Several of these players have still been productive. It is about the gap between what their teams need from them and what they have shown recently. With the calendar entering its final month, that gap has to shrink quickly.
1. Ketel Marte Has to Re-establish Himself as Arizona's Difference-Maker
Ketel Marte's September matters for two reasons: the Diamondbacks need his bat for the playoff race, and Marte needs to re-establish the level of trust that made him one of the franchise's most important players.
Arizona recently got the three-time All-Star back after a multi-week absence. Before that interruption, his season had already been quieter than his best years. Marte entered the stretch run with 21 home runs but an OPS well below the level he produced from 2023 through 2025. For a 32-year-old hitter who has been one of the most dangerous middle-infield bats in baseball, that decline is noticeable.
The Diamondbacks are trying to edge San Diego for the final NL wild-card place. That makes every extra-base hit and every high-leverage plate appearance meaningful. Marte does not have to carry the offense by himself, but Arizona needs the version of him who can lengthen the lineup and punish mistakes from both sides of the plate.
There is also a longer-term layer. Marte's relationship with the club has become less straightforward, and his 10-and-5 rights give him full control over any potential trade. If Arizona eventually wants to consider a major roster decision, a productive September helps everyone. It reminds other teams how good Marte can be while giving the Diamondbacks a better chance of making October in the first place.
2. Aaron Judge's Biggest Test Is Simply Getting Back on the Field
Aaron Judge's task is different from everyone else's on this list. There is almost nothing left for him to prove as a hitter. The question is whether his body will allow him to become the center of the Yankees' lineup again before the postseason begins.
Judge has been sidelined since late May with a fracture in his right ribcage. Before the injury, the three-time AL MVP still owned a .907 OPS through 59 games. That would be an excellent season for almost anyone else; for Judge, it felt like a relatively quiet start compared with his usual dominance.
The encouraging sign is that his rehab has advanced to on-field batting practice, running and defensive work. Aaron Boone has acknowledged that a return during New York's next homestand is possible. If that happens, the Yankees should have enough regular-season runway to let Judge rebuild his timing without asking him to carry the offense immediately.
The stakes are enormous. New York is already positioned to reach October, but Judge changes the shape of every postseason matchup. Opponents have to alter bullpen plans, protect against the home run and deal with the possibility that one mistake can flip a game. If Judge looks physically comfortable by the end of September, the Yankees become much easier to view as the team to beat in a wide-open American League.
3. Zack Wheeler Needs to Prove His Midseason Slide Is Over
Zack Wheeler already accomplished the hardest part of his season by returning from a blood clot and thoracic decompression surgery. His first 15 starts were remarkable: a 10-1 record and a 2.13 ERA after such a serious medical setback would have been impressive even without considering his age and workload.
The problem is what happened next. Since his All-Star snub, Wheeler has gone through a rough stretch in which his ERA climbed sharply over eight starts. His most recent outing was much better, as he limited the Angels to one earned run across six innings, but the larger concern is command. Too many walks can turn playoff innings into bullpen emergencies very quickly.
The Phillies do not need Wheeler to be their only ace because Cristopher Sánchez and Jesús Luzardo give Philadelphia one of the strongest top-of-rotation combinations in the sport. What they need is for Wheeler to make the group deeper rather than shakier.
In a postseason series, the difference between having two reliable starters and three is massive. A strong Wheeler allows the Phillies to avoid overworking Sánchez and Luzardo, gives the bullpen more predictable rest and creates a rotation capable of surviving a long October run. September is his chance to show that the ugly stretch was fatigue and adjustment rather than a warning that his body cannot sustain another postseason workload.
4. Roman Anthony Has to Show Boston Can Count on Him in October
Roman Anthony's challenge is less about production than availability. The 22-year-old looked like a future centerpiece during his rookie season, when he produced 2.8 WAR in only 71 games. The problem is that injuries keep interrupting the moments when Boston most needs him.
A left oblique strain kept Anthony out of last year's Wild Card Series against the Yankees. This season, a right wrist sprain cost him nearly four months. He has now returned to a Red Sox team that has kept itself relevant despite spending most of the year without one of its most talented hitters.
The upside is obvious. Anthony gives Boston another dynamic left-handed bat, improves the top half of the order and adds the kind of athleticism that can change a short series. The concern is whether the Red Sox can build a postseason plan around a player who has not yet been able to string together a full healthy season.
That makes the next few weeks unusually important. Anthony does not have to chase individual numbers. He needs consistent at-bats, consistent defensive reps and normal recovery from one game to the next. If he can simply remain in the lineup through the end of September, Boston will enter October with much more confidence that its young star can finally participate in the games the franchise has been building toward.
5. Shohei Ohtani's Health Could Define the Dodgers' Three-Peat Bid
No player changes a postseason roster more than Shohei Ohtani because he can influence a game in two completely different ways. That is why even a minor physical concern becomes a major Dodgers story.
Ohtani had been tracking toward another return to the mound before his progress stalled. Through 14 starts, he had been spectacular: an 8-2 record, 1.79 ERA and 10 strikeouts per nine innings. Los Angeles can survive without those innings because Tarik Skubal, Yoshinobu Yamamoto, Blake Snell and Tyler Glasnow give the club absurd rotation depth.
The more important concern may be the effect of Ohtani's left knee on his hitting and baserunning. Even if he never pitches again this season, the Dodgers need him comfortable enough to drive the ball, run the bases normally and stay in the lineup every day.
Los Angeles already proved in 2024 that it can win a championship with Ohtani functioning only as a designated hitter. The 2026 roster is even better equipped to absorb the loss of his pitching workload. What the Dodgers cannot replace is the unique offensive pressure he creates at the top of the lineup.
September is therefore less about whether Ohtani reaches the mound and more about whether his body trends in the right direction. If he enters October moving freely and swinging normally, the Dodgers remain the obvious favorite. If the knee keeps limiting him, the gap between Los Angeles and the rest of the National League becomes much smaller.
6. Cal Raleigh Needs One More Surge to Salvage Seattle's Season
Cal Raleigh was never going to repeat a 60-home-run season easily. The problem is that his follow-up has not merely been less historic—it has been genuinely difficult.
Raleigh has spent much of 2026 fighting through poor contact and an extremely low batting average. August offered some hope. He hit nine home runs during the month, including a three-homer performance against Philadelphia, and posted an .877 OPS even while batting below .200.
For Seattle, that kind of power still matters because the lineup has failed to provide consistent support for a strong pitching staff. Julio Rodríguez, Taylor Ward, J.P. Crawford and others have also had uneven years, leaving the Mariners with less margin for error than expected.
Raleigh cannot erase the disappointment of the first five months, but he can change the ending. If his August power carries into September and the Mariners climb back into the postseason picture, the season becomes easier to understand as a long slump followed by a meaningful recovery rather than a complete collapse after one historic year.
The biggest thing to watch is whether the home runs are accompanied by better overall at-bats. Seattle needs more than solo shots. It needs Raleigh controlling the strike zone, creating traffic and making pitchers work. If that happens, the Mariners still have enough rotation quality to make a late charge in a division that has never fully separated.
7. Ronald Acuña Jr. Can Turn a Quiet Season Into a Dangerous October
Ronald Acuña Jr. at his best is one of the few players who can dominate a game without needing to hit a home run. He can change an inning with speed, power, plate discipline and the constant pressure he creates on the defense.
That version has appeared only in flashes this season. After returning from a torn left ACL and producing a strong 2025, Acuña has been limited again in 2026 and has not generated his usual offensive impact. His batting average and OPS have both fallen well below his typical standards.
The Braves have been good enough to lead the NL East anyway. That should worry the rest of the league. Atlanta has built a contender without receiving an MVP-level season from one of the most explosive players in baseball.
If Acuña heats up over the final few weeks, the Braves change from a strong division leader into a much more dangerous October opponent. Opposing pitchers would have to deal with his speed and power at the top of the lineup before facing the deeper run-producing bats behind him.
There is also a confidence component after another injury-interrupted year. A player who has been through two significant knee injuries does not simply need healthy test results. He needs enough game action to trust his body at full speed. September gives Acuña a chance to build that momentum before the intensity of playoff baseball arrives.
8. Trea Turner Has to Rediscover the Player Philadelphia Paid For
Trea Turner's 2026 season has been difficult on both sides of the ball. After winning the NL batting title in 2025, he has fallen back to a .241 average. His defense has also moved sharply in the wrong direction, with errors and advanced metrics both showing a major regression.
That combination is a problem because Turner's contract and role are built around star-level impact. The Phillies do not need him to win an MVP award, but they do need more than an ordinary shortstop if they are going to get through a deep National League field.
The encouraging part is that Turner's skill set can change quickly when his confidence returns. He still has elite speed, can create extra-base hits and has enough track record to believe a hot month is possible. The Phillies have seen this before: when Turner gets comfortable, he can become one of the most dangerous transition hitters in the sport, turning singles into doubles, taking extra bases and forcing mistakes.
September should be about simplifying the game. Philadelphia needs cleaner defensive innings and more controlled offensive at-bats rather than Turner trying to force his way back into form with one swing. If he can build a few weeks of steady production before the postseason, the Phillies' lineup becomes much harder to navigate from top to bottom.
9. Brandon Woodruff Needs to Show He Can Still Help Milwaukee This Year
Brandon Woodruff's problem has never been effectiveness when healthy. Since returning from major shoulder surgery, he has posted a 3.11 ERA. The issue is that the shoulder has allowed him to make only 21 starts, and another bout of inflammation again interrupted his season.
At one point, it looked as though Woodruff might be headed for another surgery. Instead, the shoulder improved enough for him to begin throwing again. The Brewers have publicly left open a small possibility that he could return before the season ends.
Even a bullpen role would matter. Milwaukee does not need to force Woodruff back into a full starter's workload if his arm is not ready for it. A healthy version capable of giving the club two or three high-quality innings could become an unusual postseason weapon, particularly in a series where managers are constantly looking for matchups between traditional starters and late-inning relievers.
There is also a personal reason for Woodruff to finish the year on the mound. He is approaching free agency, and proving that his shoulder can handle competitive innings would change the conversation around his offseason market.
The best-case scenario is not necessarily five starts in September. It is enough healthy game action to show that the latest setback did not permanently derail his comeback. If Woodruff can do that while helping the Brewers in October, it would be one of the better late-season stories in the league.
10. Manny Machado Needs a Strong Finish to Lift San Diego Into October
Manny Machado has still hit for power this season, but the complete offensive profile has not looked like the one San Diego expects from a franchise cornerstone. He entered September with 24 home runs, a .220 batting average and a 98 OPS+, meaning his overall production has been almost exactly league average.
That is not enough for a player with Machado's history or contract. The Padres have him signed through 2033, and at age 34, every prolonged dip naturally raises questions about how much of the decline is temporary and how much could be age-related.
The good news is that San Diego does not need Machado to carry the entire lineup. Fernando Tatis Jr. and Jackson Merrill have both been excellent since the All-Star break. If Machado simply joins them with a strong final month, the Padres can become much more dangerous than their current wild-card position suggests.
The race with Arizona adds urgency. A cold two-week stretch could end San Diego's season before October even begins. A hot Machado can swing several games by himself because he still changes the lineup when he is driving the ball to all fields and forcing pitchers to challenge the hitters around him.
September will not define Machado's career. His résumé is already too strong for that. But it can define the Padres' 2026 season. If he looks like a star again, San Diego has the talent to be an uncomfortable Wild Card Series opponent. If his second-half OPS remains ordinary, the Padres may not get that chance.
These 10 players enter September in very different situations, but the common theme is pressure. Judge and Anthony need to prove they can stay healthy. Ohtani and Woodruff are trying to show their bodies can support meaningful October roles. Wheeler, Turner, Raleigh, Acuña, Marte and Machado are trying to rediscover levels of performance their teams have relied on in the past.
The regular season is long enough for slumps to feel permanent. October is short enough for one good week to make them irrelevant. The players who finish September strongest may end up changing not only their own seasons, but the entire playoff bracket.
