Athletics vs. Arizona Diamondbacks

Platform comparison

Market context

An MLB game between the Athletics and Arizona Diamondbacks is set for 9:40PM ET on 20 July, with the market asking whether the Athletics will win. In prediction markets, a YES share pays out if the Athletics win, while a NO share pays out if they lose; the current 40% YES price implies the crowd expects Arizona to win roughly six times out of ten.

Historical MLB data shows that teams with inferior recent form and higher ERA often face implied win probabilities below 45%, mirroring this market’s setup. The Athletics enter at 42–56 with a 5.04 ERA, while Arizona stands at 50–48 with a 4.59 ERA, and ESPN Analytics projects a 65.5% win chance for the Diamondbacks, aligning closely with the 60% NO probability in the market [2][3].

Traders should monitor starting pitcher announcements and any late-injury updates, as both starters project for early exits, increasing reliance on bullpens and amplifying volatility [4]. DraftKings’ latest preview notes the Diamondbacks are favoured with a projected score of 6–4, reinforcing the crowd’s lean [1]. With the settlement window ending 28 July 2026, any postponement will keep the market open until completion, while a cancellation or tie resolves at 50–50.

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). That keeps the comparison honest — a single canonical probability across the row, with the venue-by-venue trade-offs spelt out in the columns next to it.

Resolution & payout

At resolution the UMA oracle takes over: a proposer posts the outcome with a bond, any token holder can dispute within two hours. Without dispute the result is accepted and the smart contract distributes USDC instantly.

On Kalshi (CFTC-regulated) resolution runs through their in-house clearing engine in USD. Betfair Exchange settles after match end in the account's local currency. Manifold pays no cash — only its in-platform "mana" currency.

FAQ

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 Polymarket cost to trade?

Polymarket itself charges 0% — the only cost is the Polygon network fee, typically under $0.01 per transaction. Off-chain venues like Kalshi or Betfair charge 2-7% commission.

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.

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.