Mariners vs. Red Sox Dunkel MLB Picks, Predictions and Prop Bets - June 21

The Boston Red Sox will look to sweep the Seattle Mariners at T-Mobile Park on Sunday, at 4:10 p.m. ET. Logan Gilbert (5-4, 3.43 ERA) will start for the Mariners, who are 39-39 this season and first in the AL West. Payton Tolle (3-4, 2.93 ERA) is expected to start for the Red Sox, who are 31-43 and fifth in the AL East.

Sportsbooks have made the Mariners a decent moneyline favorite (-130) at home over the Red Sox (+106). The game's total is set at 7.5.

Mariners vs. Red Sox Odds, Game Time

• Game day: Sunday, June 21, 2026
• Game time: 4:10 p.m. ET
• Location: Seattle, Washington
• Stadium: T-Mobile Park
• Favorite: Mariners (-130)
• Underdog: Red Sox (+106)
• Over/under: 7.5

How to Watch Mariners vs. Red Sox

• TV Channel: SEAM and NESN
• Live Stream: Fubo (Watch for free)

Bet now on FanDuel Sportsbook!

Mariners vs. Red Sox: Betting the Moneyline

• The Mariners have gone 37-34 in games they were listed as the moneyline favorite (winning 52.1% of those games).
• Boston has been victorious in 12, or 42.9%, of the 28 contests it has been chosen as underdogs in this season.
• Seattle has a record of 29-20, a 59.2% win rate, when favored by -130 or more by oddsmakers this season.
• The Red Sox have a win-loss record of 5-11 when favored by +106 or worse by bookmakers this year.
• The implied moneyline probablility in this matchup gives the Mariners a 56.5% chance to win.
• The moneyline set for this matchup implies the Red Sox have a 48.5% chance of coming away with a victory in the contest.

Mariners vs. Red Sox: Betting the Spread & Total

• The Mariners have combined with opponents to go over the total 38 times this season for a 38-37-3 record against the over/under.
• Boston and its opponents have hit the over in 32 of its 74 games with a total this season.
• The Mariners have covered just 37.2% of their games this season, going 29-49-0 ATS.
• In 74 games with a line this season, the Red Sox have a mark of 31-43-0 against the spread.