Orioles vs Cardinals Prediction Market Odds, August 27, 2026
| Spread | Total | ML | Best ML | |
|---|---|---|---|---|
â–¶Orioles | -1.5 40%32% | O 8.5 47%47% | 53%52% | 53% Kalshi |
â–¶Cardinals | +1.5 60%68% | U 8.5 53%53% | 49%49% | 49% Kalshi |
| Spread | Total | Moneyline | Best ML | |
|---|---|---|---|---|
â–¶Baltimore Orioles | -1.5 | O 8.5 | 53% Kalshi | |
â–¶St. Louis Cardinals | +1.5 | U 8.5 | 49% Kalshi |
Baltimore is the 52.5c side on the cross-platform average (53c Kalshi, 52c Polymarket) with St. Louis at 49c on both books, which makes a 65-68 road team the marginal favorite over a 66-68 home team on the morning of August 27, 2026. The Orioles lead the series 2-0 after a 13-1 and an 8-7 win, the Cardinals have lost five straight, and Trevor Rogers (9-8, 4.14 ERA) is the only announced starter. The board has traded $82.8K in lifetime volume across two platforms.
Baltimore arrives at Busch Stadium on Thursday holding a 2-0 series lead and the shorter price, and that combination is the entire story of the Orioles vs Cardinals board. The Orioles took the opener 13-1 and the middle game 8-7, and the market has responded by installing a 65-68 road team as the marginal favorite over a 66-68 home team. First pitch is 2:15 PM ET, a time confirmed independently by the Kalshi contract ticker (KXMLBGAME-26AUG271415BALSTL) and the ESPN scoreboard listing for August 27, 2026.
Orioles vs Cardinals Market Context
As of the morning of August 27, 2026, Baltimore is the 52.5c side on the cross-platform average, 53c on Kalshi and 52c on Polymarket. St. Louis is 49c on both books. Kalshi's two sides sum to 102c, so roughly 2c of overround sits in the quote and the normalized read is Baltimore 52% and St. Louis 48%. That is a pick'em with a lean to the visitor, and it matters more than the raw cent because home field in a modern MLB game is usually worth something close to 4c. The market is not just calling this even, it is discounting St. Louis below what the standings alone justify. ESPN's matchup predictor takes the other side of that argument at 50.7% for the Cardinals, a gap of roughly three points against the board.
Form explains most of the difference. St. Louis has lost five straight, dropping all three at home to Philadelphia (7-6 in ten innings, 12-3, 6-4) before Baltimore came in and won by twelve and then by one. The Cardinals sit 66-68 overall and 32-36 at Busch, third in the National League Central and 16.5 games behind Milwaukee. Baltimore is 65-68 and 31-34 on the road, fourth in the American League East and 14 games behind Tampa Bay. Neither club is playing for position, so the board is pricing pitching, health and the last five days of results rather than any postseason stake.
The pitching matchup is lopsided on information alone. Trevor Rogers is Baltimore's announced starter at 9-8 with a 4.14 ERA over 24 starts, 132.2 innings, 114 strikeouts, 36 walks and a 1.24 WHIP. St. Louis had not posted a probable starter to the league's schedule feed as of publication, and an unnamed opposing starter is one of the cleanest reasons a market shades toward the team that has named one. If the Cardinals announce a front-of-rotation arm before first pitch, the 49c side is the one that moves.
The bats are close enough to be a coin flip. Baltimore has scored 604 runs in 133 games (4.54 per game) with a .718 team OPS and 163 home runs, led by Pete Alonso at .276 with 32 home runs and 91 RBI. St. Louis has scored 593 in 134 (4.43 per game) with a .698 OPS and 139 home runs, led by Alec Burleson at .291 with 98 RBI and Jordan Walker's 27 home runs. Team pitching is nearly identical: Baltimore 4.19 ERA and a 1.34 WHIP, St. Louis 4.24 and 1.34. The injury lists are where the separation shows. St. Louis is without shortstop Masyn Winn (thumb), Everson Pereira (hand) and starters Andre Pallante (elbow) and Hunter Dobbins (forearm). Baltimore is without Tyler O'Neill (shoulder) and Blaze Alexander (hand), plus a bullpen missing Felix Bautista (shoulder) and Ryan Helsley (elbow) and a lineup missing Ryan Mountcastle (oblique).
The line has not moved. The board carries 201 price snapshots, and the captured window on the moneyline runs about four hours, from roughly 8:00 PM ET on August 26 to just before midnight. Across that window Kalshi's Baltimore contract went from 52c to 53c and never left a one-cent band, Kalshi's St. Louis contract opened and closed at 49c inside a 48c to 50c range, and Polymarket's Baltimore side held 52c across every capture. That is a stable market, not a drifting one, and the window is short enough that it says nothing about where the price sat earlier in the week. The cross-platform gap is one cent on Baltimore and zero on St. Louis, so neither book is showing a materially different number on the moneyline. The series opener on August 25 priced the same two clubs, and the 13-1 result is the single biggest input into how this finale is quoted.
What the Orioles vs Cardinals Spread and Total Imply
The run line and the total are Polymarket-only on this board, so read them as one book's opinion rather than a consensus. Baltimore at -1.5 trades 40c and St. Louis at -1.5 trades 35c. Those two sum to 75c, which leaves roughly a quarter of the distribution to a one-run margin in either direction, exactly what a pick'em moneyline should produce. Push the ladder out and Baltimore -2.5 is 30c and St. Louis -2.5 is 23c, so the book prices a blowout in either direction at under a third.
On totals, over 7.5 is 54c, over 8.5 is 48c and over 9.5 is 38c, which makes 8.5 the effective market number with the over a shade under even money. Season rates sit slightly above that: Baltimore's 4.54 runs per game plus St. Louis's 4.43 comes to 8.97 combined, and this series has already produced a 14-run game and a 15-run game. The counterweights are Busch Stadium, which suppresses run scoring relative to league average, and a forecast of 83 degrees with no precipitation and gusts to 13 mph, conditions that neither inflate nor deflate the number. The first-inning run market is the one prop with two books on it, priced 47c on Kalshi and 45c on Polymarket for a 46c average.
When the Orioles vs Cardinals Market Resolves
The moneyline resolves to the team that wins the game outright when it goes final at Busch Stadium on August 27, 2026, with a scheduled 2:15 PM ET first pitch. Extra innings are included, and there is no draw outcome. The run line settles on the final margin and the totals settle on combined runs scored by both clubs, including any extra frames. Both books settle from the official league box score, generally within a few hours of the final out. If the game is postponed and replayed on a later date, or suspended and completed later, each platform applies its own rain-out and suspension rules; a game that never counts as official voids to the pre-trade state rather than paying a side.
Key Orioles vs Cardinals Catalysts
- Announced starters: Trevor Rogers (9-8, 4.14 ERA, 1.24 WHIP over 132.2 innings) is the only named pitcher on the board, and the Cardinals naming an arm is the most likely single price mover before first pitch.
- Five-game St. Louis skid: the Cardinals have lost three to Philadelphia and two to Baltimore, including 13-1 on August 25, which is what pushed a sub-.500 road team to favorite status.
- Cross-platform agreement: Kalshi has Baltimore 53c and Polymarket 52c, a one-cent gap, so neither venue carries a meaningfully different number on the game winner.
- Bullpen depth: Baltimore is working without Felix Bautista and Ryan Helsley, which is the argument for the over 8.5 at 48c in a game the moneyline calls even.
- Model versus market: ESPN's matchup predictor gives St. Louis 50.7% while the normalized board gives Baltimore 52%, a three-point disagreement that resolves on one afternoon of baseball.
Related Orioles vs Cardinals Markets
This is the third game of a three-game set, and the August 25 series opener carries the cross-platform pricing that preceded Baltimore's 13-1 win. For the club chasing St. Louis in the standings, the Brewers at Mets board tracks the National League Central leader, while the Astros at Yankees board and the Rays at Tigers board cover the American League contenders Baltimore is measured against. The full day's slate with live Kalshi and Polymarket quotes is on today's MLB board, and every baseball market on the platform is indexed under baseball prediction markets.
Resolution Criteria
The moneyline resolves to the team that wins the game outright when Baltimore at St. Louis goes final at Busch Stadium on August 27, 2026, first pitch scheduled for 2:15 PM ET. Extra innings count toward the result and there is no draw outcome, so one side pays $1 per share and the other pays $0. The Polymarket run line settles on the final margin of victory and the totals settle on combined runs scored by both teams, including extra innings. Both Kalshi and Polymarket settle from the official league box score, typically within a few hours of the final out. If the game is postponed to a later date, suspended and resumed, or shortened before it becomes an official game, each platform applies its own rain-out and suspension rules, and a contest that never counts as official voids rather than paying either side.
Key Factors
- Trevor Rogers (9-8, 4.14 ERA, 1.24 WHIP, 132.2 innings) is Baltimore's announced starter and the only named pitcher on the board
- St. Louis had not posted a probable starter to the league schedule feed as of publication, the most likely single price mover before first pitch
- St. Louis has lost five straight, including 13-1 on August 25 and 8-7 on August 26 to Baltimore
- Kalshi has Baltimore at 53c and Polymarket at 52c, a one-cent gap that leaves no meaningfully better number on either venue
- Baltimore's bullpen is without Felix Bautista (shoulder) and Ryan Helsley (elbow), the argument for over 8.5 runs at 48c
- ESPN's matchup predictor gives St. Louis 50.7% against a normalized board read of Baltimore 52%
What are the current Orioles vs Cardinals odds?
As of the morning of August 27, 2026, Baltimore trades at 52.5c on the cross-platform average, 53c on Kalshi and 52c on Polymarket. St. Louis is 49c on both books. Kalshi's two sides sum to 102c, so the normalized read is Baltimore 52% and St. Louis 48%.
Where can I trade the Orioles vs Cardinals market?
Both Kalshi and Polymarket list this game. The Kalshi event ticker is KXMLBGAME-26AUG271415BALSTL and Polymarket runs it under its mlb-bal-stl event. The board has traded $82.8K in lifetime volume across the two platforms, with the St. Louis moneyline contract carrying $74.5K of it.
Who is favored in Orioles vs Cardinals?
Baltimore, narrowly, at a normalized 52% implied probability despite being the road team and 65-68 on the season. ESPN's matchup predictor disagrees and gives St. Louis 50.7%, so the model and the market are about three points apart on a game both call close to even.
When does the Orioles vs Cardinals market resolve?
It settles on the final score of the 2:15 PM ET game at Busch Stadium on August 27, 2026, using the official league box score. Extra innings count, and settlement typically posts within a few hours of the final out.
What should I watch before Orioles vs Cardinals resolves?
The St. Louis starting pitcher announcement is the biggest open variable, since Baltimore has named Trevor Rogers and the Cardinals had not as of publication. Watch also whether the over 8.5 at 48c moves, given this series has already produced a 14-run game and a 15-run game.