Miami Marlins vs. St. Louis Cardinals

Platform comparison

Market context

The Miami Marlins and St. Louis Cardinals face off at Busch Stadium on 28 June for a 2:15pm ET MLB contest, with the Cardinals favoured to win and the Marlins currently holding a zero per cent implied probability of victory on the prediction market. This stark divergence from sportsbook lines—where the Marlins sit at +107 moneyline and the Cardinals at -127 [1]—suggests the prediction market is pricing in a near-certain outcome, whereas traditional bookmakers still assign the Marlins a meaningful chance. Historical cases of similar zero-implied-probability contracts in MLB often resolve when one team suffers a critical injury or pitching collapse; for instance, in 2024, a Marlins game saw their implied win probability drop to 1% after their ace starter was pulled mid-game due to a shoulder issue, leading to a decisive loss [2].

Traders should monitor the starting pitchers’ pre-game warm-ups and any late-injury announcements, particularly regarding Tyler Phillips (Marlins) and Kyle Leahy (Cardinals), whose recent form could shift the odds dramatically [2]. Phillips holds a 3.02 ERA while Leahy sits at 4.09, creating a tangible pitching advantage that some analysts believe could favour the Marlins despite the zero per cent market price [4]. The total is set at 9.5 runs, and if the game sees a high-scoring affair, the run-line bet on the Marlins +1.5 could become attractive if the Cardinals fail to cover by two runs [1]. Any delay or postponement would keep the market open, but a cancellation would resolve it 50-50, adding a layer of contingency risk for those betting on the Marlins.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Miami Marlins vs. St. Louis Cardinals 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.

How does resolution work?

Through the UMA Optimistic Oracle on Polygon: a proposer submits the outcome, a two-hour challenge window opens, and USDC payouts settle automatically once the result is final.

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 Best Prediction Markets trigger KYC only above $1,500 of lifetime trading volume; under that you trade pseudonymously with a single wallet address.