Seattle Mariners vs. Pittsburgh Pirates

Platform comparison

Active sub-markets

Market context

The underlying event is an MLB game between the Seattle Mariners and the Pittsburgh Pirates at PNC Park on 23 June 2026, with the Mariners entering as the first-place team in the AL West (40–39) and the Pirates sitting at 39–39 in the NL Central[2]. The crowd-implied probability of 0% for a Mariners win is anomalous given their superior record and George Kirby’s probable pitching role against the Pirates[6]. Historically, such extreme odds in single-game MLB markets have preceded either a data error in the resolution feed or a sudden, unannounced roster change, as seen in past cases where a starter was scratched minutes before game time without immediate public notification[4].

A power-user approaching this programmatically would first validate the probable pitcher lineups via the official MLB Gameday feed, checking for any late scratches or bullpen dependencies that could shift the win probability[8]. The primary catalysts to monitor are the starting lineups released 30 minutes before the 6:40 PM ET start, any weather advisories for Pittsburgh, and the Pirates’ recent struggle to reverse negative trends, which CBS Sports highlighted as a key factor entering this matchup[4]. Traders should also watch for conditional order triggers on betting bots that react to lineup confirmations, as these often correct mispriced odds within minutes of official announcements. The settlement window ending 30 June 2026 allows for a postponed game, meaning the market remains open until completion, which adds a layer of dependency on real-time game status feeds[1].

Sources: 1 · 2 · 3 · 4 · 5

Methodology

We track Seattle Mariners vs. Pittsburgh Pirates on the five venues with material liquidity for prediction markets. Live odds come from the Polymarket Polygon order book — the only source that ships real-time data under an open licence. For Kalshi, Betfair and Manifold we list platform attributes (fee, KYC, settlement, payment) instead of fabricated odds, because their APIs use non-comparable contract definitions.

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

Where can I trade this market with the lowest fees?

On Polymarket App UK, 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?

Polymarket App UK 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 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, Polymarket App UK 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.