Sinner's US Open Odds Fall 16 Points After Knee Treatment in Turin

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Why Jannik Sinner's US Open Chances Just Dropped 16 Points to 33%

Jannik Sinner's implied probability of winning the US Open Men's Singles title has fallen 16 percentage points to 33% on Kalshi and Polymarket after reports that the World No. 1 is undergoing shockwave therapy on his right knee in Turin. The defending Wimbledon champion has not played a competitive match since the All England Club, and his team has stated he will only travel to New York if he is "completely recovered," with a decision expected within days, according to AS.

Three days ago, Sinner sat at 49%. The contract bottomed at 28% before recovering to 33%, suggesting the market initially priced in a genuine withdrawal risk before moderating. The 16-point drop is the largest repricing of any top contender this tournament cycle.

Prediction-market view

Resolved Sep 13, 2026

Final prices, venue by venue

This market settled on September 13, 2026, so nothing below is tradeable. These are the last prices each venue published before settlement, not live quotes.

The timing aligns with Spanish-language reports published on August 17 and 18. Sinner celebrated his 25th birthday over the weekend in Turin, then was seen training at Circolo della Stampa Sporting in what his camp described as an evaluation session, not a full practice. According to La Gazzetta dello Sport (cited in the AS report), the shockwave treatment targeted inflammation in the knee, and while the response has been "favorable," the conditional language around his participation is doing the damage in prediction markets.

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US Open Men's Singles Odds: Who Gains Ground if Sinner Falters?

A 16-point decline from a market leader does not vanish. That probability redistributes across the field, and the primary beneficiaries tell their own story. Carlos Alcaraz, who defeated Sinner in last year's US Open final, is the most obvious inheritor. But Alcaraz carries his own fitness question mark: a wrist injury that has nagged him since April. Alexander Zverev, whom Sinner beat in the Wimbledon final just weeks ago, also stands to gain, as does Novak Djokovic, who has publicly compared his career trajectory to Sinner's in recent comments.

If Sinner were to withdraw entirely, his 33% would likely split primarily between Alcaraz and Zverev, with smaller allocations to Djokovic and a long tail of dark horses. The fact that Sinner still holds 33%, not 15% or lower, tells us the market believes participation remains more likely than not. This is a fitness discount, not a withdrawal price.

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Sinner's US Open Win Probability Over Time

The three-day chart reveals a move that accelerated rather than drifted. From 49% on August 17, the contract dropped steadily through August 18 as the knee treatment reports circulated, hitting its 28% floor before buyers stepped in. The 5-point recovery from that trough to the current 33% suggests a pocket of traders who view the selloff as overdone, particularly given that Sinner's camp has not ruled out participation.

The steepness of the initial decline, nearly 21 percentage points from peak to trough, indicates the market was caught off guard. Sinner had been priced as a near-coinflip favorite coming off a dominant 2026 season that included the Sunshine Double (Indian Wells and Miami without dropping a set) and a Wimbledon title defense over Zverev. The absence of competitive match play since early July, combined with the knee news, erased that premium in under 72 hours.

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The Case Against Sinner: What Would Have to Be True for the Market to Be Wrong?

The strongest bear case is straightforward: Sinner has not played a competitive match in over five weeks, he is receiving active medical treatment on a load-bearing joint, and his own team is hedging publicly about participation. If he does arrive at Flushing Meadows, he would do so without any hard-court preparation tournaments, a disadvantage for a player whose US Open record includes a 2024 title but also early exits when his form was not sharp.

Head-to-head dynamics compound the risk. Alcaraz leads the rivalry in Grand Slam encounters and has already beaten Sinner in a US Open final. Zverev pushed Sinner to four sets at Wimbledon despite losing, and the German's hard-court game is arguably his strongest surface. A less-than-100% Sinner facing either in the latter rounds would be a genuine upset candidate, not the prohibitive favorite his 49% price implied last week.

There is also the question of conditioning. Shockwave therapy is a recovery tool, not a cure. If the underlying inflammation is structural rather than acute, the two-week window before the August 30 start date may not provide enough runway. The market's current 33% price essentially says: Sinner probably plays, but he is no longer the clear best bet to win seven matches over two weeks on hard courts.

The next 48 hours, when Sinner's team is expected to confirm or deny travel to New York, will determine whether 33% is a discount or still too generous. Live pricing across all contenders is available in the US Open Men's Singles Winner market.