Padres vs. Mariners Prediction Odds, Probable Pitchers, Prop Bets for Sunday, May 17

Sunday Night Baseball features an interesting matchup between two playoff hopefuls, as the Seattle Mariners host the San Diego Padres.

San Diego is second in the NL West right now, sitting nine games over .500, but it has struggled on offense, ranking in the bottom 10 in the league in OPS and runs scored. The Padres have won behind a strong pitching staff, and they have a starter making his season debut on Sunday.

Veteran Lucas Giolito will make his first appearance in a Padres uniform, and he’ll take on Seattle All-Star George Kirby, who has a 2.84 ERA in nine starts in 2026.

Kirby has been extremely effective for the Mariners, and he’s a big reason why they’re favored at home despite being under .500 so far in 2026.

Can Seattle finish off this series with a win?

Let’s dive into the odds, a player prop to bet and my prediction for this interleague showdown.

Padres vs. Mariners Odds, Run Line and Total

Odds via DraftKings Sportsbook

Run Line

Padres +1.5 (-162)
Mariners -1.5 (+134)

Moneyline

Padres: +139
Mariners: -168

Total

7.5 (Over -107/Under -112)

Padres vs. Mariners Probable Pitchers

San Diego: Lucas Giolito (0-0, 0.00 ERA)
Seattle: George Kirby (5-2, 2.84 ERA)

Padres vs. Mariners How to Watch

Date: Sunday, May 17
Time: 7:20 p.m. EST
Venue: T-Mobile Park
How to Watch (TV): NBC/Peacock
Padres record: 27-18
Mariners record: 22-25

Padres vs. Mariners Best MLB Prop Bets

Mariners Best MLB Prop Bet

George Kirby UNDER 5.5 Hits Allowed (-124)

This season, Kirby has given up 52 hits in 57.0 innings of work, allowing six or more hits in five of his nine outings. So, why take the UNDER in this matchup?

Well, the San Diego offense has really struggled all season, ranking dead last in MLB in batting average. So, Kirby should be able to keep the Padres in check, even if he works deeper into this game.

The Mariners righty has an expected BAA of just .229 this season, and he ranks in the 89th percentile in barrel percentage and the 93rd percentile in ground ball percentage. The Padres have the fewest number of hits in MLB this season, and I don’t see that changing on the road on Sunday.

Padres vs. Mariners Prediction and Pick

Earlier today, I shared in SI Betting’s MLB Best Bets column why I’m betting on Seattle in this series finale:

The Seattle Mariners are off to a slow start in the 2026 season, sitting three games under .500 heading into Sunday night’s clash with the San Diego Padres.

Both of these teams rank in the bottom half of MLB in OPS and runs scored, though the Mariners (16th and 18th in those categories) have hit the ball better than the Padres (22nd and 29th) so far this season.

So, I’m going to back Seattle on Sunday with George Kirby (2.84 ERA) on the mound. The Mariners are 6-3 when the young righty is on the bump this season, and he’s taking on Lucas Giolito, who is making his first start of the 2026 season.

San Diego is nine games over .500, but it actually has a worse run differential (plus-2) than the Mariners (plus-11) in the 2026 season.

I’ll gladly back Kirby in this matchup, as he has been just as good as advertised this season, posting a 2.88 expected ERA while ranking in the 83rd percentile or better in chase rate, walk percentage and barrel percentage.

Pick: Mariners Moneyline (-168 at DraftKings)

Odds refresh periodically and are subject to change.

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