Mariners vs Royals Prediction, Odds, Moneyline, Spread & Over/Under for June 30

Odds updated as of 9:11 p.m.

The MLB schedule on Monday includes the Seattle Mariners facing the Kansas City Royals.

Before you do any MLB betting on this matchup at FanDuel Sportsbook, here's everything you need to know.

Mariners vs Royals Game Info

• Seattle Mariners (43-40) vs. Kansas City Royals (39-45)
• Date: Monday, June 30, 2025
• Time: 9:40 p.m. ET
• Venue: T-Mobile Park -- Seattle, Washington
• Coverage: ROOT Sports NW and FDSKC

Mariners vs Royals Odds & Moneyline

• All MLB odds, betting lines and prop bets are available on FanDuel Sportsbook.
• Moneyline: SEA: (-164) | KC: (+138)
• Spread: SEA: -1.5 (+134) | KC: +1.5 (-162)
• Total: 7 -- Over: (-120) | Under: (-102)

Mariners vs Royals Probable Starting Pitchers

Probable Pitchers: George Kirby (Mariners) - 1-4, 5.40 ERA vs Michael Wacha (Royals) - 4-7, 3.33 ERA

The Mariners will give the nod to George Kirby (1-4, 5.40 ERA), who is eyeing win No. 2 on the season, and the Royals will counter with Michael Wacha (4-7, 3.33 ERA). Kirby's team is 1-6-0 against the spread this season in his starts. When Kirby starts a game and his team is the favorite on the moneyline, they have a record of 2-3. The Royals have gone 8-8-0 against the spread when Wacha starts. The Royals have been the underdog on the moneyline in 10 of Wacha's starts this season, and they went 6-4 in those matchups.

Mariners vs Royals Prediction & Pick

All MLB win probability predictions and picks are according to numberFire.
Prediction: Mariners win (56.2%)

Mariners vs Royals Moneyline

• Seattle is a -164 favorite on the moneyline, while Kansas City is a +138 underdog on the road.

Mariners vs Royals Spread

• The Royals are at the Mariners, and are +1.5 on the runline. The Royals are +134 to cover the spread, and the Mariners are -162.

Mariners vs Royals Over/Under

• The over/under for Mariners-Royals on June 30 is 7. The over is -120, and the under is -102.

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Mariners vs Royals Betting Trends

• The Mariners have been favorites in 51 games this season and have come away with the win 28 times (54.9%) in those contests.
• This season Seattle has been victorious six times in 13 chances when named as a favorite of at least -164 on the moneyline.
• Contests with the Mariners have gone over the total set by oddsmakers in 44 of 81 chances this season.
• In 81 games with a line this season, the Mariners have a mark of 35-46-0 against the spread.
• The Royals have been the moneyline underdog 51 total times this season. They've gone 24-27 in those games.
• Kansas City is 5-3 (winning 62.5% of its games) when it has played as a moneyline underdog of +138 or longer.
• The Royals have combined with opponents to go over the total 31 times this season for a 31-50-2 record against the over/under.
• The Royals have a 43-40-0 record against the spread this season (covering 51.8% of the time).

Mariners Player Leaders

• Cal Raleigh has 84 hits and an OBP of .388, both of which are best among Seattle hitters this season. He has a .275 batting average and a slugging percentage of .643.
• Among qualified hitters in MLB, his batting average ranks 48th, his on-base percentage ranks eighth, and he is second in slugging.
• Raleigh hopes to build on a three-game hitting streak in this matchup. During his last five outings he is hitting .176 with a double and seven walks.
• Julio Rodriguez leads Seattle in slugging percentage (.409) thanks to 26 extra-base hits. He's batting .259 with an on-base percentage of .317.
• Among qualified batters, his batting average ranks him 74th, his on-base percentage 103rd, and his slugging percentage 97th.
• Rodriguez has picked up at least one hit in three straight games. During his last five outings he is hitting .364 with a double and an RBI.
• J.P. Crawford is batting .277 with a .373 slugging percentage and 30 RBI this year.
• Randy Arozarena has been key for Seattle with 72 hits, an OBP of .357 plus a slugging percentage of .395.
• Arozarena brings a two-game hitting streak into this matchup. In his last five games he is hitting .300 with a double, two walks and two RBIs.

Royals Player Leaders

• Bobby Witt Jr. has totaled 94 hits, a team-high for the Royals. He's batting .285 and slugging .491 with an on-base percentage of .338.
• Including all qualifying hitters, he is 30th in batting average, while his on-base percentage is 64th and he is 28th in slugging.
• Witt heads into this game on a three-game hitting streak. In his last five games he is batting .318 with three doubles, a home run and three RBIs.
• Maikel Garcia paces his team with a .371 OBP, and has a club-leading .485 slugging percentage. He has a batting average of .314.
• He ranks eighth in batting average, 22nd in on-base percentage and 33rd in slugging percentage in the majors.
• Vinnie Pasquantino has nine doubles, a triple, 12 home runs and 25 walks while hitting .270.
• Jonathan India has 16 doubles, four home runs and 30 walks while batting .246.

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