Red Sox vs. Mariners odds, line, prediction, start time: 2025 MLB picks, June 18 best bets from proven model

The Boston Red Sox battle the Seattle Mariners in a key American League matchup on Wednesday afternoon. Boston won the series opener 2-0 on Monday, but Seattle won Tuesday’s matchup 8-0. The Red Sox (38-37), who have won six of seven, are 16-20 on the road this season. The Mariners (37-35), who have won four of five, are 20-18 on their home field in 2025.

First pitch from T-Mobile Park in Seattle is set for 4:10 p.m. ET. The Red Sox have won five of the past nine meetings with the Mariners. Boston is a -120 favorite on the money line (risk $120 to win $100) in the latest Red Sox vs. Mariners odds from DraftKings Sportsbook, while the total number of runs Vegas thinks will be scored, or the over-under, is 6.5. Before making any Red Sox vs. Mariners picks, be sure to see the MLB predictions and betting advice from SportsLine’s proven computer model.

The SportsLine Projection Model simulates every MLB game 10,000 times. It enters Week 13 of the 2025 MLB season on a 37-30 run on top-rated MLB sides picks. It has excelled in making home run prop picks, returning more than 35 units of profit over the past two months. Anybody following at sportsbooks and on betting apps could have seen strong returns.   

Now, the model has set its sights on Red Sox vs. Mariners and just locked in its picks and MLB predictions. You can head to SportsLine now to see the model’s picks. Here are several MLB odds and betting lines for Mariners vs. Red Sox, which you can get in on with a DraftKings promo code or a FanDuel promo code.

Why the Mariners can win

Seattle is expected to start right-hander Luis Castillo (4-4, 3.29 ERA). In 14 starts this season, he has logged 79.1 innings, allowing 75 hits, 29 earned runs and 26 walks with 67 strikeouts. He is coming off a solid performance in his last outing, despite receiving a no-decision. In a 7-2 win over the Cleveland Guardians on Friday, he pitched six innings, allowing three hits, two earned runs and three walks with seven strikeouts.

Helping lead the Mariners’ offense is shortstop J.P. Crawford. In 70 games this season, he is hitting .294 with 10 doubles, six homers, 29 RBI and four stolen bases. He was 3-for-3 with two walks and one run scored in a 4-3 win over Cleveland on Saturday. He was 3-for-5 with a double and one RBI in Friday’s win over the Guardians. See which team to back at SportsLine.

Why the Red Sox can win

Left-hander Garrett Crochet (6-4, 2.24 ERA) will take the mound for Boston. He has won his last two decisions and is coming off a solid outing in a 2-1 no-decision win over the New York Yankees on Friday. In that outing, he pitched 8.1 innings, allowing four hits, one earned run and one walk, while striking out seven. In 15 starts this season, he has pitched 96.1 innings, allowing 71 hits, 24 earned runs and 28 walks with 117 strikeouts.

Among Boston’s top hitters is left fielder Jarren Duran. In 74 games this season, he is hitting .261 with 18 doubles, eight triples, five homers and 38 RBI. He has hit Seattle pitching well throughout his career. He tripled in the series opener on Monday. In 17 games against the Mariners, he is hitting .304 with six doubles, two triples, two homers and six RBI. See which team to back at SportsLine. 

How to make Red Sox vs. Mariners picks

SportsLine’s model is leaning Over on the total, projecting 7.9 combined runs, and it says one side of the money line has all the value. You can head to SportsLine to see the model’s MLB picks. 

So who wins Red Sox vs. Mariners, and which side of the money line has all the value? Visit SportsLine now to see which side you need to jump on, all from the model that has crushed its MLB picks, and find out.