Mariners vs. Padres Prediction, Odds, Probable Pitchers and Prop Bets for Sunday, May 18

The Padres and Mariners have played two low-scoring games in this series.

San Diego Padres starting pitcher Michael King is a great prop target on Sunday. / Denis Poroy-Imagn Images

The San Diego Padres are aiming to avoid a sweep at the hands of the Seattle Mariners on Sunday in what should be one of the best pitching matchups of the 2025 season.

Bryan Woo (2.84 ERA) gets the ball for Seattle against Michael King (2.32 ERA), as these two teams continue to build their case to be playoff squads in 2025. 

The Mariners have allowed just two total runs in this series, and oddsmakers have set a rather low total for Sunday’s matchup. With the Padres sitting just a game out of first in the NL West, can they pick up a win with their ace on the mound?

Let’s break down this game, including the latest odds, player props to bet and my prediction for Sunday’s series finale. 

Mariners vs. Padres Odds, Run Line and Total

Odds via DraftKings Sportsbook.

Run Line

• Mariners +1.5 (-180)
• Padres -1.5 (+150)

Moneyline

• Mariners: +124
• Padres: -148

Total

• 7 (Over -125/Under +105)

Mariners vs. Padres Probable Pitchers

• Seattle: Bryan Woo (4-1, 2.84 ERA)
• San Diego: Michael King (4-1, 2.32 ERA)

Mariners vs. Padres How to Watch

• Date: Sunday, May 18
• Time: 4:10 p.m. EST
• Venue: Petco Park
• How to Watch (TV): SDPA, ROOT Sports NW
• Mariners record: 25-19
• Padres record: 27-17

Mariners vs. Padres Best MLB Prop Bets

Padres Best MLB Prop Bet

• Michael King OVER 6.5 Strikeouts (-110)

King is one of the best strikeout pitchers in MLB, and he has a great matchup on Sunday, which I broke down in today’s best MLB prop bets for SI Betting: 

So far this season, Michael King has five starts with seven or more strikeouts, punching out 56 batters in 50.1 innings of work.

While those aren’t dominant strikeout numbers, I do love the matchup for King on Sunday. He’s taking on a Seattle offense that ranks 25th in MLB in strikeouts per game (8.91) this season.

King’s advanced numbers are great, as he ranks in the 80th percentile in strikeout percentage and the 71st percentile in whiff percentage. He should be able to set down seven or more Mariners on Sunday afternoon.  

Mariners vs. Padres Prediction and Pick

One of my favorite bets for Sunday’s action happens to be in this game, and I explained why in SI Betting’s MLB Best Bets column why the UNDER is worth a look in the West Coast clash: 

The Seattle Mariners-San Diego Padres matchup features one of the best pitching matchups of Sunday’s action.

Here’s a look at how the two starters in this game stack up in 2025:

• San Diego: Michael King (4-1, 2.32 ERA, 0.99 WHIP)
• Seattle: Bryan Woo (4-1, 2.84 ERA , 0.88 WHIP)

Both of these starters are allowing under a baserunner per inning this season, and I think that sets them up well to help this total to UNDER seven runs on Sunday.

Woo has just two starts this season where he’s given up more than three earned runs while King has a 1.89 ERA over his last eight outings. He did struggle a bit in his first outing of the season, but he’s been lights out since.

Plus, the Seattle offense is just 27th in MLB in OPS over its last 15 days. So, I wouldn't be shocked to see the Mariners struggle to get anything going with King on the mound.

Lastly, San Diego is sixth in MLB in bullpen ERA and Seattle is 11th. These teams both are too good on the mound for me to take the OVER on Sunday. 

Pick: UNDER 7 (+105 at DraftKings)

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Odds refresh periodically and are subject to change.

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