Sports

    Sinner Out at the 2026 US Open: How Prediction Markets Repriced the Year's Most Open Grand Slam

    Jannik Sinner is out of the US Open. Alcaraz surged to 34% on Kalshi. Here's how prediction markets repriced the most open Grand Slam draw in years.

    By PredictionMarkets.usSunday, August 23, 20268 min read
    Sinner Out at the 2026 US Open: How Prediction Markets Repriced the Year's Most Open Grand Slam

    Jannik Sinner arrived at Wimbledon as the world's most complete tennis player. He left as the champion, defeating Alexander Zverev in the final to claim his fifth Grand Slam title. Less than two months later, the same right knee that carried him through the grass-court summer forced a decision no fan wanted to see: the world No. 1 would not compete in New York.

    Sinner's withdrawal, announced on August 21 via social media, immediately reshaped the US Open field and sent Kalshi's markets into motion. Carlos Alcaraz—returning from a four-month absence of his own—climbed to 34 cents, while Alexander Zverev rose to 21 cents and Novak Djokovic edged to 10 cents. With the main draw beginning on August 30 at Flushing Meadows, the 2026 US Open has become the most genuinely open Grand Slam in recent memory.

    Here's what the markets say—and what they might be missing.

    The Withdrawal That Changed Everything

    Sinner's absence carries significant weight. His last competitive match was the Wimbledon final victory over Zverev in July. But throughout the North American hard-court swing, his knee failed to respond to training as expected.

    On August 21, Sinner confirmed what had been feared: "We have been back on court in Monte Carlo over the last couple of days and have realised that I still need more time to recover from my right knee issue," he wrote on social media. "I'm obviously very sad and disappointed, as New York has a special place in my heart."

    Sinner skipped both the National Bank Open in Toronto and the Cincinnati Open while receiving treatment. No confirmed return date has been announced, with his team targeting the Asian swing later in the fall season.

    His world ranking remains secure—he holds more than 5,000 points over his nearest rivals—but for the US Open draw, his departure opened every door.

    Prediction Market Odds: What Kalshi Shows Right Now

    Kalshi, a CFTC-designated contract market, operates a dedicated US Open Men's Singles Winner market. As of August 23, 2026, here is the current probability distribution for the leading contenders:

    PlayerKalshi PriceMovement (post-Sinner news)
    Carlos Alcaraz34¢▲8 points
    Alexander Zverev21¢▲7 points
    Novak Djokovic10¢▲3 points

    Three players absorbed essentially all of the probability previously assigned to Sinner. Alcaraz captured the largest share—an 8-point gain that pushed him from roughly 26 cents to 34 cents—reflecting market confidence that the defending US Open champion can make up for lost match time with raw talent alone.

    The raw numbers tell a striking story. Alcaraz's 34-cent price implies approximately a one-in-three chance of winning, despite the fact that he has not played a single competitive match since April 14 in Barcelona. His wrist injury kept him out of Roland Garros, Wimbledon, and both North American Masters events. He will step onto the court at Flushing Meadows after more than four months away from competition.

    The Case for Alcaraz—and the Risk

    Markets are rarely wrong to install a multi-time Grand Slam champion as the frontrunner, but the Alcaraz position at 34 cents carries genuine uncertainty that the price may not fully capture.

    The bull case is straightforward. Alcaraz won both the 2025 US Open and the 2026 Australian Open. He is 23 years old, arguably the most gifted player of his generation, and will arrive at Flushing Meadows with Sinner absent and no mandatory multi-set grind behind him. He is the defending champion. He owns this venue in a way that few players do.

    As The Athletic noted on August 23: "Alcaraz doesn't need to be 100 percent to win the U.S. Open, given the draw without Sinner"—pointing to his talent ceiling as a floor that most opponents cannot realistically challenge even against a physically limited version of the Spaniard.

    The bear case is real, however. Wrist injuries in tennis are notoriously unpredictable. Alcaraz will arrive without competitive match rhythm. Best-of-five Grand Slam tennis punishes players who lack form, and his only 2026 hard-court reference point was an early Indian Wells exit before the wrist gave out entirely. If anyone in the draw can exploit limited match sharpness, it is Zverev, who has developed a formula for constructing long points against Alcaraz's power game.

    Zverev's Argument: Roland Garros Champion, Top Seed, Match Fit

    At 21 cents, Alexander Zverev is the most direct beneficiary of Sinner's withdrawal in market terms. The German claimed his first Grand Slam title at Roland Garros in June—closing out a years-long narrative about his inability to convert at Majors. He then reached the Wimbledon final before losing to Sinner.

    Zverev is now the projected top seed at the US Open, having climbed from third to second in ATP Live Rankings following Sinner's effective exit from the seeding picture. He arrives with recent form. He arrives with a serve and forehand capable of neutralizing nearly anyone on hard courts. And unlike Alcaraz, Zverev will have had competitive matches from the Cincinnati draw to calibrate his level before New York.

    The counter-narrative is that Zverev's Cincinnati run ended with a squandered match point against Tommy Paul in the round of 16. Traders buying at 21 cents are betting on the version of Zverev who closed at Roland Garros—not the version who has occasionally faltered at the finish line in major events.

    At 10 cents, Novak Djokovic presents a third compelling case. The Serbian star reached the Australian Open final and Wimbledon semifinals this season. Every Grand Slam he enters may represent his last realistic opportunity to claim a 25th Major title. An open draw with question marks surrounding both Alcaraz (fitness) and Zverev (clutch delivery) creates exactly the conditions Djokovic has exploited throughout his career.

    The American Men: Home Court, Open Draw

    With Sinner absent and Alcaraz arriving without match sharpness, American men face their most legitimate US Open opportunity in several years. Ben Shelton (projected seed 8), Taylor Fritz (projected seed 9), and Frances Tiafoe are all positioned inside the top-seeded tier with potential bracket advantages in a reshuffled draw.

    Home crowd advantage at Arthur Ashe Stadium is genuine. The roar that comes with an American deep run in New York is unlike any other Grand Slam environment. In a field without a dominant Sinner-level force, draw position and psychological momentum matter in ways that rarely apply to more predictable years.

    Seedings at a Glance: The Draw Without Sinner

    With Sinner absent and no seeding points from him in play, the projected top seeds heading into the August 30 main draw are:

    1. Alexander Zverev
    2. Carlos Alcaraz
    3. Félix Auger-Aliassime
    4. Novak Djokovic
    5. Flavio Cobolli

    The seeding cutoff date is August 24, when ATP Rankings will be finalized for New York. The reshuffled order means Zverev and Alcaraz may be bracketed on opposite sides, setting up a potential final rather than a semifinal clash—a significant structural shift from the original draw projections.

    How to Track These Markets

    Kalshi's US Open Men's Singles Winner market is live and actively traded. As a CFTC-designated contract market, Kalshi is available to US residents across eligible states.

    PredictionMarkets.US aggregates live odds across platforms in one place, making it easy to monitor price shifts across each round. As the tournament progresses from qualifying this week through the main draw starting August 30, markets will move with every upset, early exit, and fitness update.

    Markets this open—with genuine uncertainty at the top of the draw—create sustained price discovery across two full weeks of competition.

    Frequently Asked Questions

    Who is favored to win the 2026 US Open after Sinner's withdrawal? As of August 23, Carlos Alcaraz leads Kalshi's US Open Men's Singles Winner market at 34 cents, implying approximately 34% probability. He is followed by Alexander Zverev at 21 cents and Novak Djokovic at 10 cents.

    Why is Alcaraz favored despite not playing since April? Alcaraz is the defending US Open champion, a two-time 2026 Grand Slam winner (Australian Open), and prediction markets assign him sufficient talent upside to win even without full match fitness. Sinner's withdrawal also removes the only player who held a clear head-to-head edge over Alcaraz in recent seasons.

    When does the 2026 US Open main draw begin? The main draw singles action begins on August 30, 2026, at Flushing Meadows in New York.

    Where can US residents access US Open prediction markets? Kalshi, a CFTC-designated contract market, offers US Open winner markets accessible to US residents. Track live odds and compare across platforms at PredictionMarkets.US.

    Can Polymarket US users access US Open tennis markets? Polymarket's US-regulated venue, operated by QCX LLC, is focused on sports event contracts. Tennis Grand Slam markets may be available; check the platform directly for current listings and availability in your state.

    What is Jannik Sinner's ranking situation after withdrawing? Sinner's world No. 1 ranking remains secure. He holds more than 5,000 ranking points over his nearest rivals, meaning his absence from the US Open does not threaten his position at the top of the ATP Rankings.

    The Market Picture

    Three different players have won the year's first three Grand Slams: Alcaraz at Melbourne, Zverev in Paris, Sinner in London. The US Open offers the year's fourth name on the trophy—and prediction markets have produced a clear, if not certain, hierarchy: Alcaraz at 34 cents, Zverev at 21, Djokovic at 10.

    Whether those prices accurately capture the hidden variable of match fitness will be tested over two weeks in New York. A player returning from four months away and a player who has won a Major for the first time are the top two contenders. That alone makes this US Open worth watching—on the court and in the markets.

    Track the shifting odds at PredictionMarkets.US as the draw unfolds from August 30.

    Sources & Verification

    Back to Articles