What Happens to Kalshi and Polymarket Props When a Player Is Injured or Doesn't Play

Most sportsbooks void a player prop when the player doesn't play. Kalshi and Polymarket don't. Kalshi and Polymarket US pay a fair price. Polymarket.com, a separate company that blocks US trading, grades most props as a No or Under.

This guide covers scratches, injuries, substitutes, postponements and combos on each platform. Our Hedge Checker compares any two of them. New to house rules? Start with our House Rules guide.

Note: Rules checked September 30, 2026. House rules can vary by state and location, and platforms change them without notice. Check the rules on the market before you bet.

Quick Reference: How Each Platform Settles Player Props

The table shows how each platform settles the cases that break hedges most often.

Check a Hedge Before You Bet

Our Hedge Checker shows how Kalshi, Polymarket US, Polymarket.com and each sportsbook settle a scratch, a substitute or a postponement, and whether your hedge still holds. It also covers NBA first basket and tennis retirements.

What Happens if a Player Doesn't Play

Kalshi

Kalshi doesn't void a prop when the player doesn't play. It settles at a fair price, between 1¢ and 99¢, taken at a different time by sport:

• NFL, soccer and NHL: before game start
• MLB and WNBA: the rules don't say

Kalshi market rules for Saquon Barkley 1+ touchdowns:

"Resolves Yes if Saquon Barkley scores at least 1+ touchdowns in the Los Angeles R vs Philadelphia Pro Football game originally scheduled for Oct 4, 2026.Outcome verified from the Governing League.

The following market refers to Saquon Barkley in the Los Angeles R vs Philadelphia Pro Football game originally scheduled for Oct 4, 2026. If Saquon Barkley is active but never takes a snap, the market settles to the fair market price before game start. Once Saquon Barkley takes at least one snap, even if nullified by penalty, the market settles based on touchdowns scored."

Kalshi's help center says its other player markets generally settle the same way.

Polymarket US

Polymarket US doesn't void a prop either. In every sport, it settles at the last fair market price, usually taken at the official announcement.

Polymarket US market rules for Saquon Barkley 1+ touchdowns:

"This market will settle to Yes if Saquon Barkley records at least 1 touchdowns (excluding passing touchdowns) in the Los Angeles Rams vs Philadelphia Eagles professional football game scheduled for Oct 4, 2026. Overtime is included if played. The listed player must participate in the game by taking at least one snap on offense, defense, or special teams, with a snap nullified by penalty counting; otherwise, the market will settle to the last fair market price. The market will settle based on the official box score at the conclusion of the game. For purposes of this market, stat corrections enforced after the game has been completed will not count. If the game is delayed, postponed, or suspended and not rescheduled to a date within two days of the originally scheduled date, the market will settle to the last fair market price. Outcome sourced from the relevant governing body."

Polymarket.com

Polymarket.com doesn't void a prop or pay a fair price. It resolves the market in the following ways:

• NFL, soccer and WNBA: No
• MLB hitters: Under
• MLB starting pitchers: 50-50 (50¢ a contract) if he doesn't start

Polymarket.com market rules for Manny Machado over 0.5 home runs:

"In the upcoming MLB game between the Chicago Cubs and San Diego Padres, scheduled for September 30 at 10:00 PM ET: This market will resolve to "Over" if Manny Machado records more than 0.5 home runs during the game. This market will resolve to "Under" if Manny Machado records less than 0.5 home runs during the game. The entire game including all extra innings will be considered. If the player is listed as inactive or otherwise does not take the field at any point, the market will resolve to "Under". If the game is postponed, this market will remain open until the game has been completed. If the game is canceled entirely, with no make-up game, this market will resolve 50-50. To know when a postponed game will be played, please check the home team's schedule on MLB.com for the listed team and look for the game described as a makeup game. The primary resolution source for this market is the official final statistics of the event as recognized by the governing body or event organizers. However, if the governing body or event organizers have not published final match statistics within 24 hours after the event's conclusion, a consensus of credible reporting may be used instead."

Polymarket.com market rules for Nick Pivetta over 3.5 strikeouts:

"In the upcoming MLB game between the Chicago Cubs and San Diego Padres, scheduled for September 30 at 10:00 PM ET: This market will resolve to "Over" if Nick Pivetta records more than 3.5 strikeouts during the game. This market will resolve to "Under" if Nick Pivetta records less than 3.5 strikeouts during the game. The entire game including all extra innings will be considered. If Nick Pivetta is not the starting pitcher for the game, this market will resolve 50-50. If Nick Pivetta starts the game but is removed at any point, this market will resolve based on the player's final recorded total. If the game is postponed, this market will remain open until the game has been completed. If the game is canceled entirely, with no make-up game, this market will resolve 50-50. To know when a postponed game will be played, please check the home team's schedule on MLB.com for the listed team and look for the game described as a makeup game. The primary resolution source for this market is the official final statistics of the event as recognized by the governing body or event organizers. However, if the governing body or event organizers have not published final match statistics within 24 hours after the event's conclusion, a consensus of credible reporting may be used instead."

What Is Last Fair Market Price?

Last fair market price is the value a prediction market assigns a contract when it can't settle Yes or No. Neither Kalshi nor Polymarket US publishes a formula.

For example, you buy 100 Yes contracts on a player to score a touchdown at 42¢. He's active but never takes a snap. If the fair price is determined to be 30¢, you get $30 back, a $12 loss.

Polymarket US usually sets it at the time of the official announcement, and trades made after that still settle at the announcement price. Kalshi's NFL, soccer and NHL props use the price before game start, so a hedge between the two can settle at different moments. If a player is ruled out an hour before kickoff and the line moves before the game starts, the two sides may settle at different fair prices.

What Happens if a Player Gets Injured During the Game

Once a player counts as having played, all three platforms settle on his stats, even if he leaves a minute into the game. In Kalshi's words, the contract settles "on the statistics actually accumulated, regardless of any in-game injury, ejection, or other removal from the game."

What Counts as Playing

On Kalshi and Polymarket US, it depends on the sport:

• NFL: one snap, even if a penalty wipes it out
• MLB hitters: a start and a plate appearance
• MLB pitchers: the start, plus one batter faced on Kalshi
• Soccer: entering the match on Kalshi, a start on Polymarket US
• WNBA and NHL: entering the game

On Polymarket.com, taking the field counts in every sport.

Most sportsbooks also grade a prop once the player has played, but a few don't. Fanatics voids MLB props if a pitcher leaves injured before facing nine batters or a batter leaves before his second plate appearance. BetMGM cancels Over player props when an NBA player leaves injured in the first quarter and doesn't return. A hedge between one of those books and a prediction market can split on an early injury.

Substitutes and Starting Lineups

A player who comes off the bench can settle differently on each platform:

• MLB hitters: Kalshi and Polymarket US pay a fair price, even if he gets a hit. Polymarket.com's rules don't say.
• Soccer: Kalshi settles on his stats. Polymarket US pays a fair price, even if he scores. Polymarket.com's rules don't say.

Kalshi market rules for Manny Machado 1+ home runs:

"Resolves Yes if Manny Machado records 1+ home runs in Chicago C vs San Diego professional baseball game originally scheduled for Sep 30, 2026 at 10:00 PM EDT.Outcome verified from ESPN, Fox Sports, and the Governing League.

Player Participation & Settlement Criteria

• If Manny Machado is scratched or not included in the starting lineup, the market will resolve to the fair market price.
• If Manny Machado starts the game but does not record a plate appearance, the market will resolve to the fair market price.
• If Manny Machado is not in the starting lineup but later enters the game, the market will resolve to the fair market price, pinch hit at bats will not count towards the market.
• If Manny Machado is in the starting lineup and records at least one plate appearance the market will settle based on home runs recorded."

Polymarket US market rules for Manny Machado 1+ home runs:

"This market will settle to Yes if Manny Machado hits 1 or more home runs in the Chicago Cubs vs San Diego Padres MLB NL Wild Card Game 2 scheduled for 2026-09-30 at 10:00PM ET. Extra innings are included if played. The listed player must be in the starting lineup and record a plate appearance; otherwise, the market will settle to the last fair market price. If the game is shortened but an official final result is declared, the market will settle based on that result. If the game is delayed, postponed, or suspended and not rescheduled to a date within two days of the originally scheduled date, the market will settle to the last fair market price. Outcome sourced from MLB."

In cup matches, Kalshi also counts extra time. Both Polymarket platforms stop at 90 minutes plus stoppage time.

For the sportsbook side, see our Lower Your MLB Risk and Matched Betting Risks with Soccer Props guides.

Postponed and Canceled Games

Kalshi

Kalshi waits, then settles at a fair price:

• NFL props: no wait
• MLB, NHL, soccer and basketball props, and most game markets: 48 hours
• Tennis and UFC: 2 weeks

Prop windows are in Kalshi's contract terms for NFL, MLB, NHL, soccer and basketball props.

Polymarket US

Polymarket US waits, then settles at the last fair market price:

• WNBA props: no wait
• NFL and MLB props: 2 days
• NHL games and props: 2 calendar days
• Soccer props and all other game lines: 2 weeks

A shortened MLB game settles on the official result.

Polymarket.com

Polymarket.com waits until the game is played. If it's canceled with no makeup game:

• Player props and most game markets: 50-50
• Soccer game markets: team wins resolve No, the draw resolves Yes

Where Polymarket.com is available, a rain-out can settle one leg of a hedge on Kalshi while the other leg stays open for days.

Combos and Parlays

On Kalshi and Polymarket US, a leg with a player who doesn't play stays in the combo at its fair price, and the payout is multiplied by that price. Polymarket US gives this example: a $10 combo paying $80, with one leg at a 60¢ fair price, pays $48. A losing leg on either platform makes the whole combo pay $0.

Polymarket.com offers combos on moneylines, spreads and totals only, so player props can't be combined there.

Can You Trade Player Props on Kalshi and Polymarket?

Yes. In September 2026, each platform offered these player props:

• Kalshi: NFL touchdowns and yards, MLB home runs, hits, total bases and strikeouts, soccer goalscorers, WNBA points and NHL goals.
• Polymarket US: NFL touchdowns and yards, MLB home runs, hits, total bases, RBIs, strikeouts and outs, soccer goalscorers (Premier League, La Liga, Serie A, Bundesliga and Ligue 1), WNBA points and rebounds, and NHL goals.
• Polymarket.com: NFL touchdowns, MLB home runs, hits, total bases, RBIs, strikeouts and outs, soccer goalscorers and WNBA points, rebounds and assists.

Availability varies by state and may change. Verify current offerings before trading.

How to Reduce Risk When Hedging Props

• Bet after lineups are out: NFL inactives are announced 90 minutes before kickoff, soccer lineups about an hour before kickoff and MLB lineups before first pitch. Most scratches are known by then.
• Pair platforms that settle the same way: Kalshi and Polymarket US both pay a fair price when a player doesn't play. Polymarket.com against a sportsbook splits, with one leg graded and the other refunded.
• Skip players who might not start: MLB hitters off the bench settle at a fair price on Kalshi and Polymarket US, and Polymarket US soccer props need a starter.
• Expect a small swing on fair prices: each exchange sets its own fair price, so a hedge between Kalshi and Polymarket US can land a little off in either direction.

How This Affects Matched Betting

Matched betting relies on one bet winning and the other losing. If a sportsbook voids its leg and the prediction market settles the other, you are at risk.

Example with Kalshi or Polymarket US

• Primary Bet : $100 on No Hit at -200 (decimal 1.50) at a sportsbook that voids if the player doesn't start. It returns $150.00.
• Hedge: $46.50 on Yes at 31¢, paying $150.00 if the player gets a hit.

You stake $146.50 and either side returns $150.00, a $3.50 profit. The Hedge Calculator sizes a hedge like this. Then the player is scratched. The sportsbook voids and the exchange sets a fair price. At 28¢ you get $42.00 back, a $4.50 loss. At 34¢ you get $51.00, a $4.50 gain. Fees are not included.

Example with Polymarket.com

This applies where Polymarket.com is available. Use the same $100 sportsbook bet, with the hedge as 150 Over 0.5 hits contracts at 31¢ ($46.50) on Polymarket.com. If the player is scratched, the sportsbook returns your $100. Polymarket.com resolves Under, and your $46.50 Over loses. You lose $46.50.

Actual returns depend on offer availability, market conditions, and individual execution.

Do not assume a prediction market voids a prop because the sportsbook on the other side does.

Finding Prop Hedges Across Kalshi, Polymarket US and Sportsbooks

Hedging a prop between a sportsbook and Kalshi or Polymarket US means converting contract prices, adding fees and sizing the hedge. DarkHorse Odds Bet Finders do it for you:

• Kalshi and Polymarket US compared with sportsbooks
• Prices shown as odds, fees included
• Every hedge sized for you

Do Kalshi and Polymarket Change Their Rules?

Yes. Every game uses the same rules on a given day, but all three platforms rewrote some rules this season without saying so. We checked about 25,000 markets from June to September 2026:

• Kalshi: in late July, MLB strikeout props counted a starting pitcher after one pitch. Now he has to face one batter.
• Polymarket US: MLB props were rewritten twice in July, adding a two-day postponement window and settling shortened games on the official result. World Cup player props in June counted substitutes. Club soccer props now require a starter.
• Polymarket.com: in July, a strikeout prop on a pitcher who didn't play resolved Under. Now a pitcher who doesn't start resolves 50-50.

Read the rules on the market before you bet. Each platform shows them on the market page:

• Kalshi: the Market Rules section below the market list. View full rules opens the contract terms.
• Polymarket US: the Market rules section. Use its dropdown to pick the market you're betting.
• Polymarket.com: the Rules tab below the markets. Select the market first.

Next, read our Introduction to +EV Betting guide.