St. Louis Cardinals vs. Arizona Diamondbacks

Platform comparison

Market context

An MLB game tonight at Chase Field pits the St. Louis Cardinals against the Arizona Diamondbacks, with the outcome determining whether a YES share resolves true or false. In prediction markets, a YES share pays out if the named event occurs—here, a Cardinals win—while a NO share pays if it does not. The crowd currently prices a Cardinals victory at 48%, implying a near-even contest where the Diamondbacks hold a slight edge.

Historically, mid-July MLB matchups between teams with similar win-loss records often resolve close to 50%, with home-ice or home-field advantage shifting probabilities by 3–5%. The Diamondbacks sit at 49–47 overall and 27–20 at home, while the Cardinals are 50–45 overall but 24–19 away, a split that aligns with the 48% implied probability and suggests the home team’s record is the primary driver of the slight bias toward Arizona [1].

Traders should monitor starting pitcher announcements, which typically drop 30–60 minutes before the 9:40pm ET start, as a late change to a weaker reliever could swing the probability by several points. Weather at Chase Field is also a factor; though the stadium is enclosed, any delay due to external factors would keep the market open until completion, per the settlement rules. No major roster injuries have been reported as of late afternoon, keeping the current probability stable [1].

Sources: 1

Methodology

We track St. Louis Cardinals vs. Arizona Diamondbacks across the five venues with material prediction-market liquidity. The probability shown is the live Polymarket mid; the comparison rows summarise how each venue treats the underlying contract — fees, KYC thresholds, settlement currency, deposit options. The highlighted row marks the cheapest route into Polymarket's order book.

Resolution & payout

Settlement runs on-chain. Polymarket's contract logic separates YES and NO shares as conditional tokens; at resolution the winning share lifts to $1.00 and the losing one to $0. The outcome input comes from the UMA Optimistic Oracle, which secures against bad resolution with a bond + dispute window.

Once finalised, the smart contract pays USDC to the holders' wallets within minutes — no withdrawal fees beyond Polygon network gas. Kalshi settles in USD via CFTC clearance, Betfair in account currency net of commission, Manifold in play-money mana with no cash-out.

FAQ

Is this market available outside the US?

Polymarket itself is geo-blocked in the US/UK/EU. Always check the legal status of prediction markets in your jurisdiction before trading.

What's the difference between YES and NO shares?

A YES share pays $1.00 if the event happens, $0 otherwise. A NO share pays $1.00 if the event doesn't happen. The market price between 0¢ and 100¢ is the implied probability.

What does Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

How fast are USDC deposits?

Polygon credits deposits after 12 confirmations — usually under 30 seconds. Withdrawals follow the same path and land back in your wallet within minutes.

Do I need to KYC for this market?

On Polymarket directly, no — it's wallet-based. Intermediary brokers like Prediction Market UK trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.