Mariners vs. Royals Prediction, Odds, Probable Pitchers and Prop Bets for Wednesday, Sept. 17

Betting odds, pick and prediction for the Seattle Mariners-Kansas City Royals matchup on Sept. 17.

Kansas City Royals designated hitter Vinnie Pasquantino is a solid prop target on Wednesday. / David Richard-Imagn Images

The Seattle Mariners are clinging to a 0.5-game lead in the AL West division heading into Wednesday’s matchup with the Kansas City Royals.

A 3-7 stretch has essentially knocked the Royals out of playoff contention, but they could play spoiler to a Mariners team that would love to avoid the wild card in the AL this season.

Seattle is set as an underdog in the odds at the best betting sites, as Bryce Miller (5.59 ERA) is on the mound against Kansas City’s Cole Ragans (5.18 ERA), who is set to re-join the Kansas City rotation after missing most of the season with a rotator cuff strain.

Can the lefty lead KC to a win at home?

Here’s a breakdown of the odds, players to watch in the prop market and my prediction for Wednesday’s action.  

Mariners vs. Royals Odds, Run Line and Total

Odds via DraftKings Sportsbook

Run Line

• Mariners -1.5 (+152)
• Royals +1.5 (-187)

Moneyline

• Mariners: -105
• Royals: -115

Total

• 8.5 (Over -116/Under -105)

Mariners vs. Royals Probable Pitchers

• Seattle: Bryce Miller (4-5, 5.59 ERA) 
• Kansas City: Cole Ragans (2-3, 5.18 ERA)

Mariners vs. Royals How to Watch

• Date: Wednesday, Sept. 17
• Time: 7:40 p.m. EST
• Venue: Kauffman Stadium
• How to Watch (TV): FDSKC, ROOT Sports NW
• Mariners record: 83-68
• Royals record: 75-76

Mariners vs. Royals Best MLB Prop Bets

Royals Best MLB Prop Bet

• Vinnie Pasquantino to Hit a Home Run (+481)

Earlier today, I shared in SI Betting’s best home run picks – Daily Dinger – why Pasquantino is a great value bet to leave the yard against Seattle: 

Kansas City Royals first baseman Vinnie Pasquantino is another player that I believe is undervalued in this market on Wednesday.

He’s taking on righty Bryce Miller, who has given up 14 home runs for the Seattle Mariners in 15 appearances in 2025. Miller also has a 5.59 ERA and has allowed 75 hits in 75.2 innings of work.

Pasquantino has limited at-bats against the Mariners righty, but he has hammered right-handed pitching overall in 2025, posting a .277 batting average with 25 of his 30 home runs. 

Over the last week, Pasquantino is hitting .320, and he’s homered six times in his last 25 games while posting a .853 OPS. 

Mariners vs. Royals Prediction and Pick

I’m not sold on either starter in this matchup, so I’m looking at the total early on Wednesday.

Ragans is making his first start since early June, and he had allowed four or more runs in each of his last three outings before landing on the injured list. He could come back and be lights out, but he’s more of an unknown entering this game.

Meanwhile, Miller has not been great all season long, posting a 5.59 ERA and an expected ERA of 5.32 – which ranks in the 10th percentile in MLB this season.

Miller has given up two or more runs in all nine of his outings since the start of May, which gives us a pretty solid floor when it comes to this market. 

While Kansas City is just 28th in runs scored this season, the Mariners are 10th, and they’re the No. 2 OVER team in MLB (82-64-5 to the OVER this season).

I’ll expect some offense in the opening frames as both of these starters aim to get their footing. 

Pick: First 5 Innings OVER 3.5 (-188 at DraftKings)

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Odds refresh periodically and are subject to change.

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