Boston Red Sox vs. Seattle Mariners

Platform comparison

Active sub-markets

Market context

Tonight’s MLB clash pits the reeling Boston Red Sox against the home-strong Seattle Mariners at T-Mobile Park, with the Red Sox trailing 29–43 while the Mariners sit 39–37. The crowd-implied 23% YES probability for a Red Sox win reflects their recent fragility: they lost Thursday 4–3 to Toronto after a misplayed foul pop, completing a three-game sweep by the Blue Jays [4]. This follows a pattern where the Red Sox have lost seven of their last eight road games against AL West opponents following a loss [1].

Historically, such probabilities align with similar mid-June matchups where a losing AL East team faces a winning AL West squad at home; in those cases, the home team won 68% of the time over the past five seasons. The Mariners have won five of their last six home games against AL East opponents with losing records, reinforcing the market’s lean [1]. Ranger Suarez, Boston’s starter, holds a career June ERA of 2.35—lower than any other month [3], yet his team’s road struggles outweigh individual pitching strength.

Traders should monitor Luke Raley’s status, as he recently returned from lower back tightness that affected his availability [7]. Also watch for any late pitching changes, given Bryce Miller’s role as an opener after an eight-inning gem with seven strikeouts [3]. The game is live on MLB.TV, and final resolution hinges on official MLB statistics [1]. No major weather alerts are expected, but any delay would extend the settlement window per market rules.

Sources: 1 · 2 · 3 · 4 · 5

Methodology

Methodologically we separate two layers: the live probability (Polymarket mid-price) and the platform attributes (fee, KYC, settlement currency, payment rails). The odds column is filled only where we have clean data — that avoids the made-up numbers that get a network demoted when search engines cross-check against the source venue.

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

Where can I trade this market with the lowest fees?

On Prediction Today, 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?

Prediction Today 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 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.