Rays vs. Mariners Prediction, Odds, Probable Pitchers, Prop Bets for Sunday, Aug. 9

The Tampa Bay Rays have a solid lead in the AL East and are looking to add to it on Sunday, as they have a chance to sweep the Seattle Mariners.

Seattle has dropped to third in the AL West and looks nothing like the team that made the ALCS in the 2025 season. The Mariners are 3.5 games back of the final wild card spot in the AL, and they’re behind New York, Boston Texas, Minnesota, Cleveland, Detroit and Baltimore entering Sunday’s action.

Emerson Hancock (3.33 ERA) will look to stop the bleeding for the Mariners, as they’ve dropped three games in a row and seven of their last 10. Tampa Bay will counter with Ian Seymour, who will make his 38th appearance in 2026.

Seymour (4.27 ERA) has worked as both a starter and reliever for the Rays, and he gave them some great length (six innings) in his last start. So, it’s possible that Tampa Bay doesn’t have to tax its bullpen (3.99 ERA) too much in this matchup.

Here’s a look at the odds, a player prop that I love and my prediction for Sunday’s series finale.

Rays vs. Mariners Odds, Run Line and Total

Odds via DraftKings Sportsbook

Run Line

Rays -1.5 (+160)
Mariners -1.5 (-195)

Moneyline

Rays: -104
Mariners: -104

Total

7 (Over -124/Under +103)

Rays vs. Mariners Probable Pitchers

Tampa Bay: Ian Seymour (8-3, 4.27 ERA)
Seattle: Emerson Hancock (6-6, 3.33 ERA)

Rays vs. Mariners How to Watch

Date: Sunday, Aug. 9
Time: 4:10 p.m. EST
Venue: T-Mobile Park
How to Watch (TV): WWOR-TV, Tampa, Rays.TV/Mariners.TV
Rays record: 70-46
Mariners record: 56-62

Rays vs. Mariners Best MLB Prop Bets

Rays Best MLB Prop Bet

Junior Caminero to Hit a Home Run (+320)

Earlier today, I shared in SI Betting’s best home run picks column – Daily Dinger – why Caminero is worth a look against Hancock and Seattle:

Tampa Bay Rays star Junior Caminero is heating up again over the last week, hitting .292 with three home runs, pushing his season total to 33.

Of those 33 home runs, 26 have come against right-handed pitching, putting Caminero in a favorable spot against the Mariners and Emerson Hancock.

The young righty has put together a strong 2026 season, posting a 3.33 ERA, but he has given up 15 home runs in 21 appearances. Hancock also ranks in just the 48th percentile in ground-ball percentage this season.

That is good news for Caminero, who is 1-for-3 against Hancock in his career. The Rays star has a 1.037 OPS over the last week of action, as he’s starting to heat up at the right time with Tampa Bay hoping to win the AL East division.

At +320, I think Caminero is worth a look, as he’s in the mix to lead MLB in home runs in 2026.

Rays vs. Mariners Prediction and Pick

There has been a lot of steam towards Tampa Bay in this game, as it opened as a +107 underdog and is now in a pick’em (-104 each side) on Sunday afternoon.

The Rays have won back-to-back games in this series by one run, and I think they’re worth a bet to complete the sweep with the Mariners reeling at this point in the season.

Seattle is now six games under .500 and has dropped three in a row, falling 3.5 games out of the final wild card spot in the American League.

Tampa Bay has been much better at home (41-18) than on the road (29-28), and it should make quick work of a Seattle team that is one of the 10 worst offenses in the league over the last month and just 16th overall in Weighted Runs Created Plus (wRC+). Tampa Bay is a top-10 team in wRC+ this season.

Seymour has pitched well for the Rays, ranking in the 71st percentile in expected ERA and the 78th percentile in expected BAA. Hancock ranks in the 47th and 42nd percentile in those two categories.

I’ll gladly bet on one of the best teams in baseball at this -104 price.

Pick: Rays Moneyline (-104 at DraftKings)

Odds refresh periodically and are subject to change.

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