Jun 21, 2026
Reds vs. Yankees prediction: Yankees favored to win Sunday's MLB matchup [6/21/2026]
Read Article Red Sox vs. Mariners prediction: Seattle favored to win Sunday's MLB matchup [6/21/2026]
Updated: | First published:
Written by Jason Bevilacqua, Head of Content and Communities
Get Boston Red Sox vs Seattle Mariners predictions for MLB Sunday.
The Seattle Mariners will face the Boston Red Sox in MLB action at T-Mobile Park on Sunday, beginning at 4:10 PM ET.
The Mariners will have Logan Gilbert (5-4, 3.43 ERA) as their starting pitcher, pitting him against Payton Tolle (3-4, 2.93 ERA) for the Red Sox.
Based on the latest simulation results, Dimers' proven MLB model predicts the Mariners as the most likely winner of the Red Sox vs. Mariners game.
This article offers further insights into Sunday's matchup, including best bets and picks.
Red Sox vs. Mariners prediction: Who will win and cover?
Using powerful machine learning and data, we have simulated the outcome of Sunday's MLB matchup between the Red Sox and Mariners, forming part of our MLB predictions coverage.
Our famous predictive model gives the Mariners a 56.8% chance of defeating the Red Sox.
According to our model, the Red Sox (+1.5) have a 61.3% chance of covering the run line, while the 6.5-run over/under has a 56.1% chance of going over,.
Red Sox vs. Mariners odds [6/21/2026]
We have sourced the best MLB odds in America for this game, which are listed here:
| Bet Type | Red Sox | Mariners |
|---|---|---|
| Run Line | +1.5 (-185) | -1.5 (+162) |
| Moneyline | +122 | -143 |
| Total | o6.5 (-115) | u6.5 (+100) |
All odds are correct at the time of publication and are subject to change.
Red Sox vs. Mariners picks and best bet
After matching our predictions against the best available odds, we can reveal our picks for each of the major markets. Plus, find our best bet for the game below:
| Bet Type | Pick | Bet Now |
|---|---|---|
| Run Line | Mariners -1.5 | +162 |
| Moneyline | Red Sox | +122 |
| Total | Over 6.5 | -115 |
According to our best MLB bets, the top play to make on this game is Over 6.5 total runs.
These picks are based on our probabilities matched against the implied probabilities from the sportsbook odds.
Red Sox vs. Mariners game-day updates and essential details
Sunday's MLB game between the Mariners and Red Sox at T-Mobile Park is scheduled to begin at 4:10 PM ET.
- Who: Boston Red Sox vs. Seattle Mariners
- Date: Sunday, June 21, 2026
- Time: 4:10 PM ET/1:10PM PT
- Venue: T-Mobile Park
Conclusion
We predict the Mariners, with a 56.8% win probability, will likely beat the Red Sox in Sunday's MLB matchup.
Additional tools and information for betting safely can be found in our Responsible Gambling hub.
Jason Bevilacqua, an expert in MLB, NHL, NBA, MLS, and NFL, delivers game previews, best bets, and props. Since 2020, as Head of Social and Community at Dimers, he has contributed insightful articles utilizing data-driven models and simulations.
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