San Francisco Giants vs San Diego Padres Prediction Market Odds, July 31, 2026
| Spread | Total | ML | Best ML | |
|---|---|---|---|---|
▶Giants | — | O 1 54%51% | 43%44% | 44% Polymarket |
▶Padres | — | U 1 46%49% | 58%56% | 58% Kalshi |
| Spread | Total | Moneyline | Best ML | |
|---|---|---|---|---|
▶San Francisco Giants | — | O 1 | 44% Polymarket | |
▶San Diego Padres | — | U 1 | 58% Kalshi |
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No spread lines available.
San Diego is the 57c home favorite for game two of this four-game set at Petco Park, and Kalshi and Polymarket print the identical 57c, so there is no cross-platform edge to take. San Francisco sits at 43c behind left-hander Carson Whisenhunt (2-1, 4.60 ERA), while the Padres had not posted a starter as of publication and are expected to cover innings with some combination of German Marquez (5.17 ERA) and Randy Vasquez (4.68 ERA). The records support the price: San Diego is 55-53 and has won five straight, San Francisco is 46-62 and 20-35 away from Oracle Park.
The Padres trade at 57c and the Giants at 43c for Friday night's game at Petco Park, first pitch 6:45 p.m. PT. San Diego (55-53) has won five in a row and sits 1.5 games out of the third National League wild card. San Francisco (46-62) is 22 games back in the NL West and 10.5 games out of the wild card. Both clubs play this series knowing the August 3 trade deadline lands the day after it ends, which puts San Diego in the buying lane and San Francisco in the other one.
Giants vs Padres Market Context
San Diego is 29-24 at Petco Park and enters on a five-game winning streak built from a three-game sweep in Miami and both ends of a July 29 doubleheader against Colorado, the last of which is on the board at the Rockies at Padres page. San Francisco is 3-2 over its last five, closing that stretch with a 16-3 win over Milwaukee, and the Giants' road split (20-35) is the single ugliest number either side brings to Petco. The Brewers at Giants board covers that series.
The 57c moneyline implies roughly a 57% win probability for San Diego. ESPN's matchup predictor has the Padres at 62.9%, so the market is pricing San Diego about 6 points cheaper than the model, and the gap tracks the pitching uncertainty rather than the records. The board carries only two market types for this game, the two-way moneyline and a first-inning run market at 46c on both books. There is no run line or total posted, so the moneyline and the first-inning contract are the whole tradeable surface here.
The pitching matchup is the reason the favorite is priced this modestly. Whisenhunt owns a 4.60 ERA across 15.2 innings and takes the ball for San Francisco. San Diego has not announced a starter, and with Nick Pivetta on the 60-day injured list and Lucas Giolito on the 15-day, the innings are expected to fall to Marquez (5.17 ERA over 11 appearances) or Vasquez (4.68 ERA) in front of a bullpen that has carried a heavy share of the load. Michael King leads the staff at a 3.38 ERA with 109 strikeouts but is lined up for Sunday, not Friday.
At the plate the edge is San Diego's power and San Francisco's contact. Manny Machado leads the Padres with 23 home runs and 64 RBI, and Fernando Tatis Jr. is hitting .286. Rafael Devers carries the Giants with 22 home runs and 60 RBI, and Luis Arraez is at .331, the highest average in the game. San Francisco is without Matt Chapman and Harrison Bader, both on the 10-day injured list, which thins the lineup behind Devers.
On line movement, the favorite has held. San Diego opened at 58c on Kalshi in the first snapshot of the session and traded there through three consecutive reads before settling at 57c, a one-cent drift with no directional story behind it. Polymarket printed 57c on both of its snapshots. Total volume across the two books is roughly $2K, thin enough that a single order can move the quote, so treat the first-inning contract at 46c as the more fragile of the two prices.
The cross-platform read is unusually clean. Kalshi and Polymarket agree to the cent on both sides of the moneyline (57c and 43c) and on the first-inning run market at 46c, so there is no spread to arbitrage and no better book to pick. That convergence is itself information: two separate order books with independent participants landed on the same number, which raises the bar for anyone taking the Giants at 43c on a read that the Padres bullpen day is worth more than three points of discount. For the rest of the slate see today's MLB board and the MLB market hub.
When the Giants vs Padres Market Resolves
The moneyline resolves to the team that wins the game at Petco Park on July 31, 2026. Each winning contract pays $1 per share and the losing side settles at zero. The first-inning contract resolves YES if either team scores at least one run in the top or bottom of the first inning. Both markets settle on the official final score once the game goes final, and a postponement or suspension pushes settlement to the completion date under each platform's rules rather than voiding the contract.
Key Giants vs Padres Catalysts
- Padres starter announcement: San Diego had no listed starter at publication, and confirmation of Marquez (5.17 ERA) or Vasquez (4.68 ERA) is the most likely single price mover before first pitch.
- Whisenhunt workload: the Giants lefty has thrown 15.2 innings on the season with a 4.60 ERA, so a short outing hands the game to two bullpens early.
- San Diego bullpen usage: the Padres have used relievers heavily during the five-game winning streak, and a taxed pen is the case for the 43c Giants side.
- Deadline positioning: San Diego is 1.5 games out of the third NL wild card with the deadline on August 3, and San Francisco at 46-62 has no such incentive.
- Lineup availability: Matt Chapman and Harrison Bader are on the 10-day injured list for San Francisco, and Machado (23 HR, 64 RBI) is the Padres bat the price is built around.
- Thin liquidity: roughly $2K of combined volume means the 57c quote can gap on a single sized order, especially in the first-inning market.
Related Giants vs Padres Markets
The series opener between these two clubs sets the table for this game and is the closest comparable board. The full day's slate of moneylines, run lines, and totals is on today's MLB page, and the league-level view with futures and team markets sits at the MLB hub. For the wider sport, including the college and international baseball boards, start at baseball.
Resolution Criteria
The moneyline resolves to the team that wins the San Francisco Giants at San Diego Padres game played at Petco Park on July 31, 2026. Winning team contracts pay $1 per share and all losing contracts settle at zero. The companion first-inning market resolves YES if at least one run is scored by either team in the first inning and NO otherwise. Both markets settle on the official final score as published by Major League Baseball once the game is complete. If the game is postponed, suspended, or shortened, settlement follows the completion date and the official-game rules of each platform rather than voiding, and Kalshi and Polymarket each publish their own tie-breaking and void language for rain-shortened contests.
Key Factors
- Padres starter unannounced at publication, with German Marquez (5.17 ERA) and Randy Vasquez (4.68 ERA) the candidates to cover innings
- Carson Whisenhunt (2-1, 4.60 ERA over 15.2 innings) starts for San Francisco
- San Diego enters 55-53 on a five-game winning streak and 29-24 at Petco Park
- San Francisco is 46-62 overall and 20-35 on the road, the worst split in the matchup
- Kalshi and Polymarket both print 57c on the Padres, leaving zero cross-platform spread
- Roughly $2K in combined volume, thin enough that one order can move the quote
What are the current Giants vs Padres odds?
As of July 31, 2026, San Diego is the 57c favorite and San Francisco is 43c. Kalshi and Polymarket both print 57c on the Padres, so the two books agree to the cent.
Who is favored in Giants vs Padres on July 31, 2026?
The Padres are favored at 57c, an implied win probability of about 57%. ESPN's matchup predictor is slightly higher on San Diego at 62.9%.
Who are the probable starting pitchers for Giants vs Padres?
San Francisco starts left-hander Carson Whisenhunt, who is 2-1 with a 4.60 ERA over 15.2 innings. San Diego had not announced a starter as of publication, with German Marquez (5.17 ERA) and Randy Vasquez (4.68 ERA) the expected options.
Where can I trade the Giants vs Padres market?
The game trades on both Kalshi and Polymarket. Kalshi lists the moneyline under the KXMLBGAME series and Polymarket runs the same matchup as an event market, with roughly $2K of combined volume as of July 31, 2026.
When does the Giants vs Padres market resolve?
It resolves when the game goes final at Petco Park on July 31, 2026, first pitch 6:45 p.m. PT. The winning team's contracts pay $1 per share and the losing side settles at zero.
What should I watch before Giants vs Padres resolves?
The Padres starter announcement is the biggest remaining variable, since a bullpen day is the main reason the market prices San Diego about 6 points below ESPN's 62.9% projection. San Diego is also 1.5 games out of the third NL wild card with the August 3 trade deadline looming.