Boston Red Sox vs. Seattle Mariners

Platform comparison

Active sub-markets

Market context

The Red Sox and Mariners are scheduled to play at T-Mobile Park in Seattle, with the matchup listed for 20 June at 10:10pm ET and carried by broadcast listings and live score pages for the same game.[4][6] In practical market terms, the contract only settles once the official final result is recorded, so any delay, suspension, or replay can keep it open until MLB completes the game; if it is cancelled without a make-up or ends tied, the market goes 50-50 under the rules.

A 38% YES price implies the market is treating Boston as the clear underdog, but not a long-shot with no path. That sits well with the way baseball prediction markets usually price away teams on the road: one game can move sharply on a starting pitcher edge, bullpen availability, or line-up news, yet the baseline is still heavily shaped by venue and series context. The most recent comparable signal from the series is Seattle’s 6-2 win in the previous game on 19 June, which can reinforce a home-field lean if traders expect the same matchup conditions to persist.[1][2][7]

For catalysts, the main items to watch are confirmed starting pitchers, late injury scratches, and any schedule changes from MLB or the Mariners, since the club has already issued one series adjustment notice for this set of games.[7] On-chain, the contract settles in USDC, so broader crypto moves matter mainly through trading appetite rather than the game outcome itself: BTC and ETH volatility, exchange liquidity, and funding-rate swings can affect how aggressively traders size positions, especially into live sports windows when capital can rotate quickly between markets.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

This page reads Boston Red Sox vs. Seattle Mariners on-chain. Polymarket's quote comes directly from the Polygon order book — the only comparable venue with on-chain settlement. Kalshi (USD, off-chain), Betfair (GBP/EUR, off-chain) and Manifold (play-money) are listed for comparison. Every CTA routes to BTC Prediction, which mirrors the Polymarket order book directly.

Resolution & payout

Settlement is on-chain via UMA Optimistic Oracle. A proposer posts the outcome with a bond, a two-hour dispute window opens, then the smart contract lifts winning conditional tokens to 1 USDC and sends payments to holders' wallets automatically. No withdrawal fees beyond Polygon gas.

Off-chain venues (Kalshi, Betfair, Smarkets) settle in local fiat through bank-side clearing — faster than SWIFT, slower than on-chain. Manifold pays no real cash.

FAQ

Where can I trade this market with the lowest fees?

On BTC Prediction, which mirrors the Polymarket order book at 0% fees. Kalshi charges up to 7% per trade; Betfair Exchange takes 2-5% commission on net winnings.

Is this market available outside the US?

BTC Prediction is available in most jurisdictions where Polymarket isn't directly accessible. Polymarket itself is geo-blocked in the US/UK/EU. Always check local regulations.

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'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.

How reliable are the quoted odds?

The YES/NO percentages are the live mid-prices of the Polymarket order book. On deep markets they move every few seconds; on thinner ones you'll see short plateaus.