Seattle Mariners vs. Kansas City Royals

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Active sub-markets

Market context

The Seattle Mariners and Kansas City Royals are scheduled to meet in a one-game MLB market where the listed side only resolves if the game is completed, with postponements left open and a cancelled game or tie settling 50-50. At a crowd-implied 52% on Seattle, the market is effectively treating this as close to a coin flip with a slight edge to the Mariners, so a model-driven approach would normally avoid treating the headline price as a strong signal by itself. In comparable recent meetings, tight scoring has been common: Kansas City won 3-2 in extra innings on 2 May, which is the sort of low-run, one-score outcome that makes run environment and bullpen usage more important than raw win total pricing.

For a programmatic trading workflow, the main inputs are the confirmed starting pitchers, line-up card timing, and any late scratch or rest pattern from day game / travel context. The most useful catalyst is the official game note cycle rather than the market headline: if Seattle or Kansas City announces a starter change, a catcher rest day, or a reliever availability issue, the fair win probability can move materially before first pitch. MLB’s recent Royals-Mariners recap from 2 May showed Kansas City surviving a dominant Emerson Hancock start, which is a reminder that a single pitcher edge does not fully settle a side market when bullpens and late-game leverage are in play.

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

Polymarket-based markets settle through the UMA Optimistic Oracle on Polygon. A proposer submits the outcome, a two-hour challenge window opens, and unchallenged proposals finalise the resolution. Payouts settle automatically in USDC the moment the result is final — no bookmaker, no delay.

Kalshi-based markets settle in USD via the CFTC-regulated clearinghouse. Betfair Exchange settles in GBP/EUR net of commission. Manifold is play-money and does not pay out real funds.

FAQ

Is this market available outside the US?

PolyGram 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.

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?

Not under $1,500 of lifetime trading volume. Above that threshold, PolyGram triggers a quick verification flow that finishes in minutes.

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.