Mariners vs Royals Prediction, Odds & Player Prop Bets Today

• The Mariners are -140 favorites vs the Royals
• Mariners vs Royals Over / Under today: 8.5 Runs
• Mariners / Royals TV Channel: FS1 | RYTV | MRTV

The Seattle Mariners (-140) visit Kauffman Stadium to take on the Kansas City Royals (+115) on May 23, 2026. First pitch is scheduled for 4:10 pm in Kansas City, MO.

This season, the Mariners are 25-27 against the spread (ATS), while the Royals are 20-29 ATS.

Mariners vs Royals Starting Pitchers Today:

• Mariners starting pitcher: George Kirby 5-3, 3.45 ERA
• Royals starting pitcher: Stephen Kolek 2-0, 4.24 ERA

Mariners vs. Royals Odds, Run Line, Over/Under & Moneyline

Based on recent trends the model predicts the Mariners will win Saturday‘s MLB game with 61.1% confidence, factoring in game simulations, recent player performances, starting pitchers and injuries.

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We’ve highlighted some favorite MLB player prop bets for Mariners players for Saturday‘s game, looking at profitable historical betting trends:

Best Mariners Player Prop Bets Today:

• Cole Young has hit the Runs Under in 19 of his last 20 games (+16.95 Units / 40% ROI)
• Luke Raley has hit the Home Runs Over in 3 of his last 6 away games (+10.20 Units / 170% ROI)
• Josh Naylor has hit the Hits Runs and RBIs Under in 14 of his last 20 away games (+8.60 Units / 40% ROI)
• Cole Young has hit the Hits Under in 13 of his last 20 games (+8.50 Units / 43% ROI)
• Randy Arozarena has hit the Singles Over in 16 of his last 25 away games (+8.15 Units / 31% ROI)

And here are some favorite MLB player prop bets for Royals players for Saturday‘s game, looking at profitable historical betting trends:

Best Royals Player Prop Best Bets Today:

• Carter Jensen has hit the Total Bases Under in 17 of his last 20 games (+14.85 Units / 53% ROI)
• Michael Massey has hit the Home Runs Over in 2 of his last 6 games at home (+13.00 Units / 217% ROI)
• Salvador Perez has hit the Hits Under in 12 of his last 20 games at home (+11.35 Units / 49% ROI)
• Isaac Collins has hit the Runs Under in 17 of his last 20 games (+11.25 Units / 29% ROI)
• Jac Caglianone has hit the Singles Under in 16 of his last 20 games at home (+9.95 Units / 32% ROI)

Mariners Best Bets Today:

• The Seattle Mariners have hit the 1st Five Innings (F5) Team Total Under in 22 of their last 35 games (+7.60 Units / 18% ROI)
• The Seattle Mariners have hit the Team Total Under in 17 of their last 25 away games (+7.55 Units / 26% ROI)
• The Seattle Mariners have hit the Game Total Under in 15 of their last 24 away games (+6.40 Units / 25% ROI)
• The Seattle Mariners have covered the Run Line in 7 of their last 10 away games (+5.85 Units / 57% ROI)
• The Seattle Mariners have hit the 1st Five Innings (F5) Moneyline in 5 of their last 6 away games (+5.00 Units / 58% ROI)

Royals Best Bets Today:

• The Kansas City Royals have hit the 1st Five Innings (F5) Team Total Under in 32 of their last 50 games (+12.10 Units / 20% ROI)
• The Kansas City Royals have hit the Team Total Under in their last 8 games (+8.00 Units / 81% ROI)
• The Kansas City Royals have hit the 1st Five Innings (F5) Moneyline in 11 of their last 20 games at home (+5.85 Units / 21% ROI)
• The Kansas City Royals have covered the 1st Five Innings (F5) Run Line in 13 of their last 20 games at home (+5.60 Units / 23% ROI)
• The Kansas City Royals have hit the Game Total Under in 28 of their last 50 games at home (+4.10 Units / 8% ROI)

Mariners Against the Spread (ATS) Record

Against the spread this season, the Mariners are 19-33 against the Run Line (-9.95 Units / -18.12% ROI).

• 25-27 when betting on the Moneyline for -11.75 Units / -16.02% ROI
• 23-27 when betting on the total runs Over for -6.85 Units / -11.91% ROI
• 27-23 when betting on the total runs Under for +1.7 Units / 2.98% ROI

Royals Against the Spread (ATS) Record

Against the spread this season, the Royals are 20-29 against the Run Line (-13.9 Units / -20.37% ROI).

• 20-31 when betting on the Moneyline for -15.7 Units / -25.74% ROI
• 22-29 when betting on the total runs Over for -9.65 Units / -17.26% ROI
• 29-22 when betting on the total runs Under for +4.85 Units / 8.61% ROI

Royals vs Mariners Home Run Prop Bets Today

Royals vs Mariners Total Hits Prop Bets Today

Royals vs Mariners Strikeout Prop Bets Today

Mariners Keys to the Game vs. the Royals

The Mariners are just 3-12 (.200) vs bottom 10 scoring offenses this season Today, they face the Royals (27th in runs scored).

The Mariners are just 19-4 (.826) when leading entering the 8th inning this season — tied for 5th lowest in MLB; League Avg: .893.

The Mariners are 10-74 (.119) when trailing entering the 8th inning since the 2025 season — 5th best in MLB; League Avg: .094.

The Mariners are 25-15 (.625) when tied entering the 7th inning since the 2025 season — tied for 3rd best in MLB; League Avg: .500.

Royals Keys to the Game vs. the Mariners

The Royals are just 15-4 (.789) when leading entering the 8th inning this season — 2nd lowest in MLB; League Avg: .893.

The Royals are just 1-14 (.067) when allowing 10 or more hits this season — 2nd lowest in MLB; League Avg: .248.

The Royals are just 3-11 (.214) when their opponents score in the first inning this season — 2nd lowest in MLB; League Avg: .369.

The Royals are just 20-31 (.392) this season — tied for 4th lowest in MLB; League Avg: .500.

Mariners Hitting Stats & Trends

The Mariners are batting just .189 against LHP this season — lowest in MLB.

Mariners hitters have an OPS of just .592 (591 PA’s) against LHP this season — lowest in MLB.

Mariners hitters have put just 30% of their swings in play with runners in scoring position this season — lowest in MLB.

Mariners hitters have an OBP of just .277 (591 PA’s) against LHP this season — 2nd lowest in MLB.

Royals Hitting Stats & Trends

Royals hitters are slugging just .207 with two-strikes this season — lowest in MLB.

Royals hitters have an OPS of just .626 (894 PA’s) on the road this season — lowest in MLB.

Royals hitters have an OPS of just .434 (989 PA’s) with two-strikes this season — lowest in MLB.

The Royals are batting just .215 on the road this season — lowest in MLB.

Mariners Pitching Stats & Trends

Mariners pitchers have a first-pitch strike rate of 67% this season — highest in MLB.

Mariners pitchers have thrown at least two strikes in their first three pitches to 70% of opposing batters this season — highest in MLB.

Mariners pitchers have walked 7% of batters this season — best in MLB.

Mariners pitchers have walked 6% of batters when facing the leadoff batter in the inning this season — 2nd best in MLB.

Royals Pitching Stats & Trends

Royals pitchers have walked 11% of batters this season — 4th highest in MLB.

Royals pitchers have induced opposing hitters to ground into 40 double plays in 362 opportunities (11%) this season — 4th best in MLB.

Royals pitchers have allowed three-ball counts to 24% of batters they faced (454/1,923 PA’s) this season — 2nd highest in MLB.

Royals pitchers have picked-off 9 runners from first base this season — most in MLB.

More MLB Reading:

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