Seattle Mariners vs. Detroit Tigers

Platform comparison

Active sub-markets

Market context

The Seattle Mariners travel to Detroit on 7 June for a regular-season matchup against the Tigers, with first pitch at 1:40 PM ET. The settlement window closes on 14 June at 17:40 UTC, allowing seven days for completion should postponement occur. The 0% implied probability shown on Polymarket reflects either a data lag or an absence of early trading volume; comparable books like Kalshi and Betfair typically display decimal odds (e.g., 1.95 for a near-even matchup) rather than binary percentages, which can obscure whether the market has genuinely priced one side at zero or simply hasn't attracted liquidity yet. Fee structures vary meaningfully across platforms—Polymarket's 2% taker fee differs from Kalshi's fixed spreads and Betfair's commission model—and these costs compound on low-probability outcomes where bid-ask spreads widen.

Historical context matters here: the Mariners and Tigers have divergent 2026 trajectories. Seattle has invested heavily in roster depth following years of competitive drought, whilst Detroit remains in a rebuild phase. Head-to-head records between these franchises show marginal variance, but home-field advantage in Detroit carries measurable weight in June when weather stabilises. Recent roster moves—including any late trades or injury updates—typically surface via MLB Trade Rumours or official team announcements in the week preceding the fixture.

Traders should monitor pitching assignments, which MLB teams typically confirm 48 hours before game time. Injury reports for key position players, particularly the Mariners' outfield depth, can shift expected run production. Weather conditions at Comerica Park in early June rarely force postponement, though the settlement terms permit reopening if cancellation occurs without a make-up date.

Methodology

This page compares Seattle Mariners vs. Detroit Tigers specifically across Polymarket, Kalshi, Betfair Exchange and Smarkets. Live odds come from the Polymarket order book; the other venues' contract details are maintained manually because their APIs aren't directly comparable. Every CTA routes to Polymarket Alternative UK, which mirrors the Polymarket order book at 0% fees.

Resolution & payout

Polymarket settles via UMA Optimistic Oracle on Polygon. A proposer posts the outcome with a bond, the two-hour window runs, then the smart contract pays USDC.

Kalshi settles USD through the CFTC-regulated clearinghouse — the cleanest variant, with heavier KYC. Betfair Exchange settles in account currency (GBP/EUR), net of 2-5% commission. Smarkets follows the same model as Betfair with a lower default 2% commission.

FAQ

Where can I trade this market with the lowest fees?

On Polymarket Alternative 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.

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.

What does it cost to trade on Polymarket Alternative UK?

Zero. Polymarket Alternative UK routes every order to the live Polymarket order book; the only cost is the Polygon network fee, typically under $0.01 per transaction.

Do I need to KYC for this market?

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