Updated August 21, 2026 · by Ben Rasa
On Friday, Jannik Sinner turned the 2026 US Open into a different tournament. The world No. 1 pulled out with the right knee injury that has shadowed him since Wimbledon, and the US Open tennis odds did something a Grand Slam futures board almost never does: repriced the whole event overnight. Between Thursday's board and Friday's, the 35 points of win probability Sinner had been holding came loose and went looking for a new home. Roughly half landed on the top two names. The strangest part of the day is the one price that never moved at all, and I'll get to that row in a minute.
The Quick Answer
Jannik Sinner withdrew from the 2026 US Open on Friday, August 21 with a right knee injury, and Carlos Alcaraz is now the men's tennis favorite at about 36% on prediction markets, ahead of Alexander Zverev near 24.5% and Novak Djokovic around 9%. The full before-and-after board, the one price that refused to move, and the honest case on every contender are below.
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Sinner Is Out: What Actually Happened
Sinner has not hit a ball in competition since he won Wimbledon in July for his fifth Grand Slam title. The right knee flared during the North American hard-court swing, cost him Toronto and Cincinnati, and on Friday it took the last major of the season too. His own words, announcing the withdrawal: "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."
That timeline matters for anyone reading the board. Right up until Friday, the market was pricing a recovery, keeping Sinner a clear favorite on the assumption that a month of rest would be enough. It was pricing the wrong thing, and the correction arrived all at once with Friday's announcement. The main draw starts Sunday, August 30, and it will now be made without the world No. 1 in it.
The Board, Before And After
Here is the men's singles winner market on Thursday night against Friday. The snapshots come from two different prediction-market venues (Kalshi's board as of August 20, Polymarket's live market on August 21), so read the comparison as directional rather than tick for tick. Directionally, it is loud.
| Player | Aug 20 (Kalshi) | Aug 21 (Polymarket) |
|---|---|---|
| Jannik Sinner | 35% | under 1% |
| Carlos Alcaraz | 29% | 36% |
| Alexander Zverev | 14% | 24.5% |
| Novak Djokovic | 7% | 9.3% |
| Ben Shelton | 7% | 7% |
| Taylor Fritz | 2% | 7.1% |
| Felix Auger-Aliassime | 2% | 3% |
| Arthur Fils | 2% | 3% |
| Jakub Mensik | 2% | 2% |
Rafael Jodar, 4% on Thursday's board, does not appear among Friday's listed prices. The row that jumps out is Taylor Fritz. His number more than tripled between the two boards, the biggest relative gain anywhere on it. A withdrawal does that to a futures market: the player never gets better, the path does. Ben Shelton is the opposite story. He sat at 7% with Sinner in the field and 7% with Sinner out. Hold that thought, because it is the most interesting quiet fact of the day.
Carlos Alcaraz Is The Favorite With An Asterisk
At 36%, which implies about +178, Alcaraz is priced as the man to beat, and the resume says he should be. He is the defending champion, he beat Sinner in last year's final, and he is chasing a third US Open title. The market did not hesitate, moving him from 29% on Thursday's board to 36% by Friday.
The asterisk is that Alcaraz has not played a competitive match since April. A wrist injury took his entire spring and summer, the layoff ran through Cincinnati, and his comeback is confirmed but completely untested. A 36% price on a player with a four-month layoff is a bet that class travels, that a two-time champion here can play himself into form across the early rounds against the soft part of a draw. Plenty of great players have done exactly that at majors. The counterpoint is that best-of-five tennis in New York heat is the worst possible place to discover your wrist is not ready, and the market is giving you almost no discount for that risk. Bettors who take the favorite here are paying a healthy-Alcaraz price for a question-mark Alcaraz.
Zverev And Djokovic: The Credentials Lane
Alexander Zverev at 24.5%, roughly +308 implied, picked up more of Sinner's abandoned probability than anyone, going from 14% to 24.5%. The case writes itself: he won the French Open in June, beating Flavio Cobolli in a five-set final for his first Grand Slam title after three runner-up finishes, and he is the only man near the top of this board arriving with a 2026 major already banked. Against a favorite who has not played since April, a major won in June is a real argument, and the market clearly agrees.
Novak Djokovic sits third at 9.3%, about +975. At 39, he no longer gets priced like a co-favorite, but traders still refuse to let him drift into the pack, and the reasoning is straightforward: hard-court majors have been his living for two decades, and the favorite above him carries an injury question he does not. The price is a bet on attrition as much as form.
Dark Horses: Fritz, Shelton, And The Price That Did Not Move
Fritz at 7.1% is the market's pick for the biggest beneficiary outside the top three. He was the runner-up at this tournament in 2024, it is his home Grand Slam, and the path to a final no longer runs through the world No. 1. A price that was 2% on Thursday saying "he beats nobody at the top" now says "he only has to beat some of them."
Now the promised row. Shelton holding flat at 7% while everyone around him climbed tells you something specific: the market pushed Sinner's 35 points to the very top of the board and to one mid-board name, Fritz, while the rest of the middle barely moved. Traders already believed in Shelton's ceiling before the news, and the withdrawal did not change their read on whether he can win seven matches. For anyone shopping the mid-board, that is the honest signal to sit with. The crowd thinks this tournament got easier only for the elite.
Medvedev And The Rest Of The Board
Daniil Medvedev at 3% is the name the market quietly wrote down and moved past, and his season explains the shrug. He is 31-13 this year with titles in Brisbane and Dubai and a final at Indian Wells, which sounds like a contender, but his best Grand Slam result in 2026 is a fourth round in Australia. The market is pricing exactly that split: a player winning plenty of tennis matches who has not solved best-of-five this season. The slower New York hard courts at least suit his grinding baseline game, which is why he holds 3% instead of drifting to 1%.
Alongside him, Arthur Fils and Felix Auger-Aliassime sit at 3%, Jakub Mensik at 2%, and a shelf of names at 1% that includes Joao Fonseca, Frances Tiafoe, and Cobolli, the same man Zverev beat in Paris. The injury attrition runs deeper than Sinner, too: Sebastian Korda is out with a back injury that requires surgery, Jack Draper's lingering arm injury has him under 1%, and Holger Rune, sidelined since rupturing his Achilles in October, sits at the bottom of the board with Sinner.
The Women's Board, For Context
Friday's news does not touch the women's draw. On Kalshi's board as of August 20, Aryna Sabalenka, the reigning champion, leads at 27%, with Iga Swiatek at 14%, Elena Rybakina at 11%, and Coco Gauff and Naomi Osaka both at 9%. The women's race is far flatter than the men's. The withdrawal list has hit the women's field harder in volume, with Victoria Mboko, Hailey Baptiste, and Emma Raducanu, out with a shin stress fracture, among the nine names already gone.
How To Read A Board Like This
A 36-cent contract on Alcaraz pays a dollar if he lifts the trophy, the exchange version of about +178 at a sportsbook. The venue matters more than usual this week: exchange prices and sportsbook lines routinely disagree in the first days after news this fresh, and our guide to Kalshi versus sportsbook odds covers when each number is the sharper reference. The bid-ask spread deserves extra attention here too, because a market still digesting a withdrawal tends to trade wide, and that gap is a real cost on any position.
Before Friday's news broke, we also ran this exact market through a panel of AI models priced blind against the crowd, and that read sits in our US Open 2026 men's champion market analysis. It is worth revisiting once the draw lands next week, because the draw is now the last big repricing event left before the first ball.
OddsShopper's tools do not carry tennis markets, so this is one tournament where we will not pretend to have a comparison surface for you. If you want to see what our experts are backing today across the sports we do cover, the free expert picks hub is the place to look.
What Friday Really Told US
Step back from the individual prices and Friday's session reads like a stress test of what the tennis market actually believes. Handed 35 free points of probability, traders sent roughly half to a returning champion with a four-month layoff and a newly minted French Open winner, tripled one American dark horse, kept a 39-year-old third, and left the rest of the board almost exactly where it was. The 2026 US Open now belongs to a small circle of names, and the market spent Friday telling you, in cents, precisely how small it thinks that circle is. When the draw comes out next week, watch whether it agrees.
- US Open Tennis Odds 2026: Kalshi Odds
- US Open 2026 Men's Odds: Kalshi's Favorites Are Both Hurt
- Cincinnati Open Winner Odds: Kalshi After The Carnage
- National Bank Open Odds: 25 Seeds Gone, Shelton Still Alive
FAQ
Who is favored to win the 2026 US Open now that Sinner is out? Carlos Alcaraz, the defending champion, leads the market at about 36% (roughly +178 implied), with Alexander Zverev next near 24.5% and Novak Djokovic third around 9%.
Why did Jannik Sinner withdraw from the 2026 US Open? A right knee injury. Sinner has not played since winning Wimbledon in July; the knee cost him Toronto and Cincinnati, and he announced on August 21 that it needs more recovery time.
When does the 2026 US Open start? Main draw singles play runs Sunday, August 30 through Sunday, September 13. The men's singles draw had not yet been made when Sinner withdrew.
Where is the 2026 US Open played? At the USTA Billie Jean King National Tennis Center in Flushing Meadows, Queens, New York, the same hard-court home the tournament has had since 1978.
How do prediction-market percentages compare to sportsbook odds? A percentage is the price of a contract that pays $1 if the player wins, so 36% implies about +178 in American odds. Exchange prices and sportsbook lines can diverge; our Kalshi versus sportsbook odds guide, linked above, explains when each is the better reference.
