Seattle Mariners vs Boston Red Sox Prediction, 8/31/2026 MLB Picks, Best Bets & Odds

Game: Seattle Mariners vs Boston Red Sox

Date: Monday, August 31, 2026

Location: Fenway Park in Boston, MA

TV: NESN

Odds/Point Spread: Seattle (+120) Boston (-144)

The Seattle Mariners (64-71) are traveling to Fenway Park on Monday where they will go up against the Boston Red Sox (73-61). The moneyline on this matchup has the Mariners at +120 and the Red Sox are priced at -144. The total is set at 8. The expected starting pitchers will be George Kirby and Payton Tolle.

Seattle is slugging .374 and have been called out on strikes 1,168 times, while taking a walk on 454 occasions. They have amassed 508 RBI's and 1,017 base knocks this year, and their batting average is sitting at .228. The Mariners have recorded 159 two-baggers as a team and have knocked 156 baseballs out of the stadium. They have accounted for 527 runs while holding a team OBP of .309. As a unit, the Seattle Mariners are notching 3.9 runs per game, which puts them at 30th in baseball.

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Their strikeout to walk ratio is 3.29 and their pitching staff has a collective WHIP of 1.24. Mariners pitchers have allowed 159 home runs and also 591 runs (13th in MLB). Seattle has relinquished 1,129 hits (8.5 per 9 innings) and 547 earned runs. The Mariners are sitting with a team earned run average of 4.13 over the course of the season (15th in the league), and they have rung up 1,146 batters. They have walked 348 opposing hitters and their FIP comes in at 3.92 as a unit for the year.

Mariners bullpen pitchers have gone to the mound with runners on base 96 times as well as having 134 appearances in high leverage situations. The relief pitchers have notched 70 holds this season (16th in the league). The Mariners relief pitchers have a save percentage of 58.8% and have stepped onto the mound in 122 save situations. They have accumulated 30 saves so far this season and have blown 21 of 51 chances to save the game. The bullpen pitchers have inherited 134 base runners this year with 30.6% of those runners crossing the plate. The Mariners have sent 409 relievers to the hill this season.

The Seattle Mariners have earned 3,576 putouts on the year, in addition to 1,106 assists and 70 errors. Their fielding percentage is at .985 which has them ranked 16th in professional baseball, and they have turned 111 double plays. The Mariners have transformed 69.1% of balls in play into outs in their 10,728 innings, which ranks them 24th in baseball.

Kirby has pitched in 784 frames and has racked up 747 K's during his pro baseball career. His earned run average is 3.67 (320 ER's allowed) and his WHIP is 1.155. He has given up 779 base hits (8.9 hits per 9 innings) and has 127 free passes. Kirby (54-44 career record) sits with a FIP of 3.62 and he has gone up against 3,218 batters during his time in the major leagues.

The Red Sox have a team slugging % of .404 and they earn 4.48 runs per game (15th in the league). They have recorded 243 two-baggers, while walking 434 times and recording 600 runs. Boston is sitting with 136 home runs for the season and 573 RBIs. They have struck out on 1,080 occasions (22nd in baseball) and have accounted for 1,120 base knocks. The Boston Red Sox have tallied an OBP of .324 as well as a batting average of .249 for the season.

The Red Sox hold a team WHIP of 1.221 in addition to having a FIP of 3.65 as a staff so far this season. They rank 10th in the league as a pitching staff in total hits allowed with 1,070. The Boston pitching staff have surrendered 500 runs this year while holding an ERA of 3.46 (458 earned runs surrendered). Their strikeout to walk ratio comes in at 8.70 (1,150 strikeouts against 386 free passes). They have given up 128 home runs and they relinquish 3.77 runs per 9 innings (3rd in baseball).

Boston bullpen pitchers hold an inherited score percentage of 29.8% out of 141 inherited runners. Their relief pitchers have stepped onto the hill 123 times in high leverage situations and on 104 occasions with runners on base. With 131 save situations, the Red Sox have recorded 80 holds in addition to 12 blown saves. They sit at 3rd in the league with a save percentage of 75.5%, and they have dispatched 412 bullpen pitchers onto the field on the season.

The Boston Red Sox have gotten 97 double plays and hold a fielding percentage of .985 (18th in baseball). The Red Sox have 1,162 assists, 72 errors and have earned 3,577 putouts during this campaign. In their 10,731 innings played, the Red Sox are sitting with a defensive efficiency of 69.7% (18th in pro baseball).

In his career, Tolle has allowed 119 base hits while accumulating 160 punch outs in 141 innings pitched. Tolle (8-7 career record) has earned a 3.44 ERA and has surrendered 7.6 hits per nine innings. He has conceded a total of 54 earned runs while holding a WHIP of 1.147 and being the owner of a FIP of 3.4. He has a strikeout to walk ratio of 3.72 and he has gone up against 579 hitters in his pro baseball career.

Who will win tonight's MLB game against the spread or moneyline?

Josh Schonwald's Pick: Take Seattle (+120)

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