The Boston Red Sox will look to continue their recent run of strong play as they play the second game of a three-game series against the Seattle Mariners at Fenway Park tonight.
These teams are capable of putting up a lot of runs, and I’ll be backing the Over in my Mariners vs. Red Sox predictions with a relatively weak pitching matchup looming.
Let’s break down tonight’s game in my free MLB picks for Wednesday, April 23.
Mariners vs Red Sox prediction
My Mariners vs Red Sox best bet: Over 10 (-102 at FanDuel)
The Boston Red Sox have won six of their last seven games, and they’ve been doing so behind an offense that is beating up on opposing pitchers. During that seven-game stretch, Boston is averaging 5.43 runs per game, and the team is putting up an average of 4.64 runs on the season, eighth-most in the majors.
The Red Sox have been particularly effective against right-handed pitching, posting a .740 OPS compared to .693 when facing southpaws. There are several excellent left-handed bats on Boston' roster, including Jarren Duran, Wilyer Abreu, and Rafael Devers, while righties Alex Bregman and Trevor Story have solid platoon splits to lengthen the lineup.
Tonight, those bats will go up against Seattle Mariners starter Emerson Hancock, who has yet to prove he can compete against major league hitting.
While Hancock has gotten some opportunity to pitch for the Mariners in each of the past three seasons, he has posted a 5.29 ERA in his 17 career starts. Hancock doesn’t get strikeouts, averaging just 5.6 per nine innings, while posting a career WHIP of 1.404. If anything, 2025 has been even worse for the 25-year-old righty, who has allowed eight earned runs on 12 hits in 5.2 innings of work over his first two starts.
We can expect the Red Sox to put up runs against Hancock, but let’s not sleep on the Mariners lineup, either. Boston starter Sean Newcomb is a 31-year-old lefty with a career 4.48 ERA. He has allowed teams to get on base to the tune of a 1.90 WHIP in his first four starts this season, and has only been somewhat effective because he has yet to give up a home run in 17.1 innings of work.
That could change for Newcomb tonight. The Mariners haven’t hit quite as well as the Red Sox this year, but one thing they do bring to the table is power throughout the lineup. Seattle has 33 homers on the year — sixth most — and catcher Cal Raleigh leads MLB with nine. That includes three home runs in just 31 plate appearances against left-handed pitching this season.
While I like the Red Sox tonight — the matchup against Hancock is hard to ignore — both offenses will thrive.
That’s especially true at Fenway Park, which remains the second-best run-scoring environment in the majors, according to Statcast data.
Mariners vs Red Sox same-game parlay (SGP)
Over 10
Red Sox moneyline
Wilyer Abreu 1+ RBI
Jarren Duran 1+ hits
I’m expecting a lot of runs tonight, and the Red Sox should have a particularly good time teeing off on Hancock.
Boston has won six of its last seven and comes into this game as a clear favorite at home, and I think it has an even bigger edge if this game hits the Over, as I expect.
I’ll also take two Red Sox players to participate in the scoring barrage, and that starts with taking Abreu to pick up at least one RBI. Abreau has knocked in 15 runs on the year, and has mashed against righthanded pitching this year, putting up a 1.027 OPS.
I’ll also take Duran to pick up a hit, as he's hit safely in nine straight and has a career .281 average against righties.
Learn how to bet a same-game parlay with these helpful tips and strategies.
Mariners vs Red Sox odds
Mariners vs Red Sox live odds
Mariners vs Red Sox opening odds
- Moneyline: Seattle +110 | Boston -130
- Run line: Seattle +1.5 (-180) | Boston -1.5 (+150)
- Over/Under: Over 9.5 (-120) | Under 9.5 (+100)
Mariners vs Red Sox trend
The Over is 4-1 in Seattle’s last five games overall. Find more MLB betting trends for Mariners vs. Red Sox.
How to watch Mariners vs Red Sox and game info
| Location | Fenway Park, Boston, MA |
| Date | Wednesday, 4-23-2025 |
| First pitch | 6:45 p.m. ET |
| TV | RSNW, NESN |
| Mariners starting pitcher | Emerson Hancock (0-1, 12.71 ERA) |
| Red Sox starting pitcher | Sean Newcomb (0-2, 3.63 ERA) |
Mariners vs Red Sox latest injuries
Mariners vs Red Sox weather
Not intended for use in MA.
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