The Seattle Mariners currently sit outside of the playoff picture, having just dropped five in a row to the Orioles and the Angels. A playoff team should have swept those series rather than going 1-5, and doing so would have Seattle delightfully positioned atop the AL West.
The Arizona Diamondbacks suffer from no such “what if” scenarios; simply meandering toward a season below .500.
My Mariners vs. Diamondbacks predictions and MLB picks know better than to trust Seattle, but perhaps the best Mariner warrants such faith. First pitch comes at 9:40 ET on Monday, June 9.
Mariners vs Diamondbacks prediction
My Mariners vs Diamondbacks best bet: Cal Raleigh home run (+270 at Caesars)
Maybe it is because the Seattle Mariners are a frustrating franchise, on the brink of AL contention, and yet looking at the playoffs as a pipe dream.
Maybe it is because the Pacific Northwest is often overlooked in sporting conversations. Or, maybe it is because catchers wear masks and are thus less marketable than other players.
Whatever the reason, Cal Raleigh is not appreciated enough. He's not simply leading the league in home runs; he's doing it by three more than Shohei Ohtani and Aaron Judge.
Raleigh keeps swinging even as the Mariners keep losing — hitting three home runs during their five-game losing streak — including two in his most recent appearance.
This enthusiasm increases when Raleigh faces a RHP, going yard 18 times on 155 at bats against them this season, a rate of a home run on 11.6% compared to just 10.4% against southpaws.
Enter Arizona Diamondbacks starter Merrill Kelly, giving up eight earned runs in his last three starts, including two homers. This logic doesn't need to extend much further. Odds of +270 suggest Raleigh has, roughly, a one-in-four chance of a home run tonight.
That is aggressive, but if he gets three ABs against RHPs tonight, logic says there is nearly a one-in-three chance Raleigh clears the fence.
With Kelly throwing at least six innings in four of his last five starts, the Seattle catcher might get three ABs against the starter alone.
Caesars QuickPick: Our Mariners vs Diamondbacks same-game parlay (SGP)
Cal Raleigh home run
Mariners team total Over 4.5
Mariners moneyline
Each leg of this same-game parlay is obviously correlated. But if Raleigh hits a home run, then it should hardly be an ask for the Mariners to score five runs. The bats were their downfall in their recent losing streak, averaging just 3.2 runs in those five contests.
Seattle tends to hold its own against right handers, and that creates value in expecting an offensive outburst to lead to a win.
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Mariners vs Diamondbacks odds
Mariners vs Diamondbacks live odds
Mariners vs Diamondbacks opening odds
- Moneyline: Seattle +130 | Arizona -160
- Run line: Seattle +1.5 (-140) | Arizona -1.5 (+118)
- Over/Under: Over 9.5 (+100) | Under 9.5 (-120)
Odds courtesy of Caesars.
Mariners vs Diamondbacks trend
The Seattle Mariners have hit the moneyline in 17 of their last 27 away games (+6.60 Units / 20% ROI). Find more MLB betting trends for Mariners vs. Diamondbacks.
How to watch Mariners vs Diamondbacks and game info
| Location | Chase Field, Phoenix, AZ |
| Date | Monday, 6-9-2025 |
| First pitch | 9:40 p.m. ET |
| TV | FS1 |
| Mariners starting pitcher | Emerson Hancock (2-2, 5.19 ERA) |
| Diamondbacks starting pitcher | Merrill Kelly (6-2, 3.43 ERA) |
Mariners vs Diamondbacks latest injuries
Mariners vs Diamondbacks weather
Odds are correct at the time of publishing and are subject to change.
Not intended for use in MA.
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