The Mariners (64-73) and the Red Sox (74-63) open a three-game series tonight at Fenway Park with both clubs looking to rebound from difficult weekends as the chase for a postseason berth continues for each.
Seattle comes to Boston after being swept in a three-game series by the Blue Jays in Toronto. The Mariners have now lost four in a row overall as the struggles on offense continue. Seattle has scored a total of four runs the past four games and been shut out in two of the four. They did not get much help from the bump either as the staff gave up 19 runs in the three games in Toronto. As a result, Seattle is now five games behind Houston in the NL West as well as five back of Cleveland for the final Wild Card position.
Boston takes the field in far better position as far as the postseason is concerned but after a disappointing trip to the Bronx that saw them lose three of four to the Yankees. The Sox split the first two games of the series but were outscored 25-3 over the final two games to drop 8.5 games in back of the Rays in the AL East and four back of the Yankees for the top Wild Card spot.
The Mariners will turn to George Kirby (9-10, 4.02 ERA) to try and change their fortunes tonight. In his most recent start against Philadelphia, Kirby allowed just one earned run over 7⅔ innings while striking out nine. It was an important bounce-back performance after two difficult starts in which he surrendered six earned runs against Milwaukee and five against Houston.
Boston counters with rookie left-hander Payton Tolle (8-6, 3.09 ERA), who has ascended to nearly the top of the rotation as the season has evolved. Tolle has been especially impressive during August. Three starts ago, he fired eight shutout innings against Toronto. Two outings ago, he struck out a career-high 14 hitters against Oakland. Most recently, he allowed just two earned runs over 5⅓ innings against Miami.
Lets dive further into today’s game and find a sweat or two.
We’ve got all the info and analysis you need to know ahead of the game, including the latest info on the how to catch first pitch, odds, recent team performance, player stats, and of course, our predictions, picks & best bets for the game from our modeling tools and staff of experts.
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Game Details and How to Watch: Mariners vs. Red Sox
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Date: Monday, August 31, 2026
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Network/Streaming: MLB.TV, Mariners.TV, NESN
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The Latest Odds: Mariners vs. Red Sox
The latest odds as of Monday courtesy of DraftKings:
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Moneyline: Seattle Mariners (+151), Boston Red Sox (-162)
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Spread: Mariners +1.5 (-155), Red Sox -1.5 (+129)
Probable Starting Pitchers – Mariners vs. Red Sox for August 31
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Red Sox: Payton Tolle
Season Totals: 125.1 IP, 8-6, 3.09 ERA, 1.09 WHIP, 141K, 35 BB -
Mariners: George Kirby
Season Totals: 147.2 IP, 9-10, 4.02 ERA, 1.33 WHIP, 126K, 34 BB
Who’s Hot? Who’s Not! Mariners vs. Red Sox
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Adley Rutschman is just 4-22 in his career against George Kirby but has homered against the righthander
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Trevor Story is 2-8 against Kirby but both hits have left the park
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Jarren Duran is 3-10 against Kirby
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Dominic Canzone has homered in 3 ABs in his career against Payton Tolle
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Payton Tolle has struck out 7+ batters in 6 of his last 8 starts
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George Kirby has struck out 4+ batters in just 1 of his last 6 starts
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Nick Sogard picked up at least 1 hit in each game against the Yankees (4-11)
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Roman Anthony returned from the disabled list yesterday and went 2-4
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Julio Rodriguez is 1-15 over his last 4 games
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Cal Raleigh has hit safely in 7 of his last 9 GP (10-29)
Top Betting Trends & Insights: Mariners vs. Red Sox
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The Mariners are an MLB-worst 51-86 on the Run Line this season
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The Red Sox are 67-70 on the Run Line this season
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The OVER has cashed 69 times in Seattle’s 137 games this season (69-61-7)
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The OVER has cashed 64 times in Boston’s 137 games this season (64-69-4)
Expert picks & predictions: Mariners vs. Red Sox for August 31
Rotoworld Bet Best Bet
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Our model calculates projections around each moneyline, spread and over/under bet for every game on the MLB calendar based on data points like past performance, player matchups, ballpark information and weather forecasts.
Once the model is finished running, we put its projection next to the latest betting lines for the game to arrive at a relative confidence level for each wager.
Here are the best bets our model is projecting for tonight’s game between the Mariners and the Red Sox:
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Moneyline: Rotoworld Bet is staying away from a play on the Moneyline.
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Spread: Rotoworld Bet is recommending a play on the Red Sox on the Run Line.
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Total: Rotoworld Bet is staying away from a play on the Game Total of 7.5
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Jay Croucher (@croucherJD)
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