Red Sox vs Orioles Prediction Market Odds, September 5, 2026
| Spread | Total | ML | Best ML | |
|---|---|---|---|---|
Sox | +1 — | O 2.5 — | 100%100% | 100% Kalshi |
Orioles | -1 — | U 2.5 — | 100%100% | 100% Kalshi |
| Spread | Total | Moneyline | Best ML | |
|---|---|---|---|---|
Boston Red Sox | +1 — | O 2.5 — | 100%100% | 100% Kalshi |
Baltimore Orioles | -1 — | U 2.5 — | 100%100% | 100% Kalshi |
Boston leads this four-game set at Oriole Park at Camden Yards 2-0 after a 6-5 win and a 1-0 shutout, and the market prices game three accordingly: the Red Sox sit at 57.5c on the cross-platform average against 43c for Baltimore as of the evening of September 4. Boston is 77-65 and holds an American League wild card spot, Baltimore is 69-73 and fifth in the AL East. First pitch is 7:05 PM ET, Sonny Gray (16-4, 2.82 ERA) against Chris Bassitt (6-4, 4.97 ERA), on a board carrying roughly $19.8K of cumulative Kalshi and Polymarket volume.
Boston arrives at 77-65 overall and 42-31 on the road, the second-best road record in the American League East, and has taken the first two games of this four-game series at Camden Yards by a combined 7-5. Baltimore is 69-73, 34-36 at home, 15 games back in the division and 2.5 games behind Cleveland for the last AL wild card spot. The Red Sox lead the season series 7-4 across 11 meetings. That is the structural gap the 57.5c cross-platform average is pricing, and it is a modest number for a matchup this lopsided on the mound.
Red Sox vs Orioles Market Context
The moneyline is the only line on this board with real depth. Boston trades at 58c on Kalshi and 57c on Polymarket, Baltimore at 43c on both, so the two venues are within a cent of each other on the favorite and exactly aligned on the underdog. There is no cross-platform value spot on the winner here, which is itself the read: the books agree, and the $15.4K sitting on the Boston moneyline leg against $3.6K on the Baltimore leg says the flow has been one-directional.
The board's snapshot history is narrow. Across the roughly two-hour capture window on the evening of September 4, Boston's Kalshi price oscillated between 57c and 58c and finished the window at 58c, Baltimore held 43c on every capture, and Boston's full-game run line held 44c. The one line that actually moved in that window was the over 10.5 runs rung, which ticked down from 32c to 30c. Nothing else on the board carries snapshot history yet, so treat every other rung as an unpriced quote rather than a line that has been tested.
The alt markets tell a tighter story than the moneyline does. Boston at -1.5 is 44c on both platforms, which implies the market gives Boston roughly a 76% chance of winning by multiple runs conditional on winning at all. Baltimore at -1.5 is 28c. The full-game total sits just under 8.5: over 7.5 is 55c, over 8.5 is 48c, and over 9.5 is 37.5c, which brackets a market expectation near 8.4 combined runs. That is a restrained number for Camden Yards, and it reflects the pitching more than the parks. Baltimore has out-scored Boston on the season at 4.51 runs per game to 4.46, but Boston's staff is fourth in MLB at a 3.65 ERA while Baltimore's is 15th at 4.15.
Recent form cuts against the price slightly. Baltimore is 5-5 in its last 10 but has lost four straight, including the first two of this series. Boston is 4-6 in its last 10, having been swept out of a three-game set at Seattle before arriving in Baltimore, so the two wins here are the correction rather than the trend. The widest quoted cross-platform gap on the whole board is 3c on the first five innings Boston run line (35c Kalshi, 32c Polymarket), and that rung has traded $0, so it is a quoting artifact and not a signal.
Red Sox vs Orioles Pitching Matchup
Sonny Gray is the reason this line is where it is. He is 16-4 with a 2.82 ERA over 25 starts and 143.2 innings, with 128 strikeouts against 37 walks and a 1.18 WHIP. Sixteen wins is the most on the Boston staff and the 2.82 ERA is the anchor of a rotation that has held opponents to 3.91 runs per game.
Chris Bassitt has been the opposite. He is 6-4 with a 4.97 ERA over 14 starts and 79.2 innings, with 55 strikeouts against 29 walks and a 1.58 WHIP. That WHIP is the number to focus on: 1.58 means Bassitt puts roughly a runner and a half on base per inning, and against a Boston lineup posting a .730 OPS that traffic is what turns a 48c over 8.5 into a live ticket. The 79.2 innings across 14 starts also means Bassitt averages under six innings per outing, which hands the game to a Baltimore bullpen that has allowed 4.66 runs per game as part of a staff ranked 15th in the league.
The run line at 44c is where the pitching edge is expressed most directly. A Gray start against a sub-six-inning opposing starter is the profile that produces multi-run wins, and the market has already priced Boston as a favorite in every meeting of this series. Baltimore's counter is the first-inning market at 47.5c for a run scoring in the top or bottom of the first, a number that has stayed flat across the captured window.
When the Red Sox vs Orioles Market Resolves
The moneyline resolves to the team that wins the game at Oriole Park at Camden Yards on September 5, 2026, first pitch 7:05 PM ET. Winning contracts pay $1 per share and the losing side settles at $0. The run line settles on the final margin, so Boston at -1.5 needs a win by two runs or more, and the total settles on combined runs scored by both teams in the official final score, extra innings included. First five innings markets settle on the score after the bottom of the fifth regardless of what follows. Kalshi and Polymarket both settle from the official Major League Baseball result once the game goes final, typically within hours of the last out. A postponement moves settlement to the completion date under each platform's rain-delay and suspended-game rules rather than voiding the contract.
Key Red Sox vs Orioles Catalysts
- Sonny Gray's command: a 1.18 WHIP and 128 strikeouts against 37 walks is the single largest input into both the 57.5c moneyline and the 48c over 8.5.
- Chris Bassitt's traffic: a 1.58 WHIP over 79.2 innings and under six innings per start puts the Baltimore bullpen in the game early.
- The run line at 44c: Boston at -1.5 is the cleanest expression of the pitching gap, and it held flat at 44c on both platforms through the captured window.
- Baltimore's four-game losing streak: the Orioles are 5-5 in their last 10 but have dropped four straight and sit 2.5 games out of the final AL wild card spot.
- Cross-platform alignment: Kalshi and Polymarket are within 1c on the favorite and identical at 43c on Baltimore, so the winner market offers no venue-selection edge tonight.
- The total near 8.4: over 7.5 at 55c, over 8.5 at 48c, and over 9.5 at 37.5c bracket a low number for two offenses separated by 0.05 runs per game.
Related Red Sox vs Orioles Markets
Game two of this series is priced and settled at Red Sox vs Orioles on September 4, where Boston won 1-0. The division context lives on the AL East winner market, which Tampa Bay leads at 83-57 with Boston seven games back, and the wider stakes sit on the AL pennant board and the World Series market. Full team boards and every remaining game are on the Boston Red Sox hub and the Baltimore Orioles hub, and the rest of tonight's slate is on the MLB hub.
Resolution Criteria
Resolves to the team that wins the game at Oriole Park at Camden Yards on September 5, 2026, with a scheduled first pitch of 7:05 PM ET. The winning team's moneyline contract pays $1 per share and the losing contract settles at $0. Spread contracts settle on the final margin (Boston -1.5 requires a two-run win or better) and total contracts settle on combined runs in the official final score including extra innings. First five innings markets settle on the score after the bottom of the fifth inning. Kalshi and Polymarket both settle from the official Major League Baseball box score once the game is final. If the game is postponed or suspended, each platform settles on the completion date under its own rain-delay rules rather than voiding the contract.
Key Factors
- Sonny Gray (16-4, 2.82 ERA, 1.18 WHIP over 143.2 innings) is the primary input into the 57.5c Boston moneyline
- Chris Bassitt (6-4, 4.97 ERA, 1.58 WHIP) averages under six innings per start, exposing a Baltimore staff allowing 4.66 runs per game
- Boston -1.5 held flat at 44c on both Kalshi and Polymarket through the captured snapshot window
- Baltimore has lost four straight and sits 2.5 games behind Cleveland for the final AL wild card spot
- Kalshi and Polymarket are within 1c on the favorite and identical at 43c on Baltimore, so there is no venue edge on the winner
- The full-game total brackets 8.4 runs (over 7.5 at 55c, over 8.5 at 48c, over 9.5 at 37.5c) despite the two offenses being separated by 0.05 runs per game
What are the current Red Sox vs Orioles odds?
As of the evening of September 4, 2026, Boston is the 57.5c favorite on the cross-platform average (58c on Kalshi, 57c on Polymarket) and Baltimore is 43c on both platforms. The board carries roughly $19.8K in cumulative volume.
Who is favored in Red Sox vs Orioles on September 5, 2026?
Boston is favored at an implied probability near 57.5%, backed by Sonny Gray's 2.82 ERA and a 77-65 record that includes a 42-31 mark on the road. Baltimore is 69-73 and fifth in the AL East.
Where can I trade the Red Sox vs Orioles market?
Both Kalshi and Polymarket list this game. Kalshi carries the deeper alt-market ladder with run lines to -3.5 and team totals, while Polymarket carries inning-by-inning props including a 56c first-inning tie contract.
What is the Red Sox vs Orioles run line and total?
Boston at -1.5 trades at 44c on both platforms and Baltimore at -1.5 trades at 28c. The full-game total sits just under 8.5 runs, with over 8.5 at 48c and over 9.5 at 37.5c.
When does the Red Sox vs Orioles market resolve?
It resolves when the game goes final at Oriole Park at Camden Yards on September 5, 2026, first pitch 7:05 PM ET, with settlement from the official Major League Baseball box score usually within hours of the last out.
What should I watch before Red Sox vs Orioles resolves?
Watch the confirmed lineups and any late change to the Chris Bassitt start, since his 1.58 WHIP is the main lever on both the 44c Boston run line and the 48c over 8.5. Game four of the series follows on September 6.