Boston Red Sox (31-43) vs. Seattle Mariners (39-39) June 21, 2026 4:10 pm EDT The Line: Seattle Mariners -136 / Boston Red Sox +113; Over/Under: 6.5 (Get latest betting odds)
The Boston Red Sox and the Seattle Mariners meet Sunday in MLB action from T-Mobile Park. We will look at this from a betting perspective and determine the best bets for this game. Here’s a Boston Red Sox vs. Seattle Mariners prediction.
The Boston Red Sox will send out Payton Tolle for the start here and Tolle is 3-4 with a 2.93 ERA and 60 strikeouts this season. Logan Gilbert will start for Seattle and is 5-4 with a 3.43 ERA and 92 strikeouts this season.
The Boston Red Sox come into this game looking to add on to their 5-1 win over the Mariners from Saturday to improve to 31-43 this season. After this series, the Red Sox will head on the road for a series against the Colorado Rockies.
Wilyer Abreu leads the Red Sox with 76 hits including 16 doubles, a triple, 8 home runs and 34 RBIs while Trevor Story has 34 hits with 7 doubles, 3 homers and 19 RBIs and Marcelo Mayer’s added 40 hits with 7 doubles, 3 home runs and 18 RBIs as well. Roman Anthony has 25 hits with 5 doubles, a triple, a home run and 5 RBIs so far this season while Jarren Duran has 57 hits with 9 doubles, 12 home runs and 37 RBIs as well this season. Willson Contreras has added 72 hits with 11 doubles, 16 homers and 44 RBIs of his own on the year.
The Seattle Mariners come into this game looking to shake off a loss at the hands of the Red Sox last time out to sit at 39-39 this year. After this series, the Mariners will head on the road for a series against the Pittsburgh Pirates.
Luke Raley has 14 home runs and 35 RBIs this season. Cole Young’s added 70 hits with 10 doubles, a triple, 6 home runs and 33 RBIs and Cal Raleigh has 28 hits with 4 doubles, 7 home runs and 20 RBIs as well this season. Randy Arozarena has 76 hits with 18 doubles, 7 home runs and 33 RBIs as well on the year. Josh Naylor also has 68 hits with 8 home runs and 32 RBIs as well on the year. Julio Rodriguez has also added 75 hits with 15 doubles, 13 home runs and 36 RBIs.
I’m backing Boston here. So far, the Red Sox have thrown back-to-back lefties at Seattle and the Mariners have had no answer so why not one more in Tolle who has been solid for Boston this season. Gilbert’s been unusually weak at home this season and has been far better on the road which we’re not used to seeing, and I think the Red Sox get the job done here. Give me Boston.