MLB Prop Bets: Seattle Mariners vs Boston Red Sox (June 21, 2026)
The Boston Red Sox (31-43) face the Seattle Mariners (39-39) at T-Mobile Park on Sunday at 4:10pm (ET). Let's take a look at the MLB Prop Bets for the matchup. Payton Tolle is the probable pitcher for the Red Sox, while Logan Gilbert is the probable pitcher for the Mariners. The Mariners are favored to win at -143, while the Red Sox are at +119. The total runs line is set at 6.5, with OVER at -114 and UNDER at -105.
- The Red Sox (-186) have a 31-43 Run Line record this season, while the Mariners (+153) hold a record of 32-46.
- The Red Sox have a 33-38-3 O/U record this season (meaning 33 games have gone over the total runs line, 38 have gone under and three have resulted in a push). The Mariners have a 38-36-4 O/U record.
Scoring Insights
- The Red Sox are averaging 4.0 runs per game this season (29th in the league). Comparatively, the Mariners are averaging 4.1 (23rd).
- In the field, the Red Sox are allowing 4.0 runs per game this season (7th in the league), while the Mariners are allowing an average of 3.9 runs (5th).
Let's take a look at how these teams perform in some other key statistical areas.
Batting Insights:
Batting Average
- Looking at their batting averages this season, the Red Sox are at .244 (ranking 16th in the Major leagues), while the Mariners are batting .232 (27th).
Home Runs
- In terms of total home runs this season, the Mariners have hit 97 (T8th in the Major Leagues). Meanwhile, the Red Sox have managed 63 (29th).
Runs Batted In
- Finally, looking at their runs batted in, the Red Sox have recorded 280 RBIs to rank 30th in the MLB this season. Comparatively, the Mariners have recorded 314 RBIs to rank 18th.
Pitching Insights:
Earned Run Average
- The Mariners have an earned run average of 3.66 this season (5th in the Majors), while The Red Sox have an ERA of 3.86 (8th).
Strikeouts
- Turning our attention to total strikeouts, the Red Sox have recorded 622 this season, ranking 18th in the MLB. Meanwhile, the Mariners rank 7th for total strikeouts, recording 679.
Opponent Batting Average
- Opponents are batting an average of .240 against the Mariners this season (13th in the Major Leagues). Comparatively, the Red Sox's opponents are at .243 (19th).
First Innings Moneyline
- Here are their first innings moneyline records in 2026.
| Total | Home | Road | Favorite | Underdog | Neutral | Last 10 | |
|---|---|---|---|---|---|---|---|
| Red Sox | 10-27-37 | 6-10-21 | 4-17-16 | 6-14-25 | 4-13-12 | 0-0-0 | 1-3-6 |
| Mariners | 21-17-40 | 13-10-17 | 8-7-23 | 21-15-34 | 0-2-6 | 0-0-0 | 3-2-5 |
Lead After Three Innings
- Here are their records after the first three innings in 2026.
| Total | Home | Road | Favorite | Underdog | Neutral | Last 10 | |
|---|---|---|---|---|---|---|---|
| Red Sox | 23-32-19 | 13-15-9 | 10-17-10 | 15-16-14 | 8-16-5 | 0-0-0 | 4-6-0 |
| Mariners | 35-25-18 | 20-12-8 | 15-13-10 | 30-23-17 | 5-2-1 | 0-0-0 | 3-4-3 |
NRFI/YRFI
The NRFI market is paying -135 and the YRFI is paying +105.
- The NRFI is 35-39 in Red Sox games this season. The Mariners have a 35-43 NRFI record.
Last Time They Met
The Red Sox recorded a 5-1 victory over the Mariners at T-Mobile Park yesterday. Wilyer Abreu went yard en route to that victory, hitting a home run to go with 2 RBIs. The Red Sox have now won three straight against the Mariners.
