Jul 28, 2024; Chicago, Illinois, USA; Kansas City Royals shortstop Bobby Witt Jr. (7) hits a grand slam against the Chicago White Sox during the eight inning at Guaranteed Rate Field. Mandatory Credit: Kamil Krzaczynski-Imagn Images

Seattle Mariners vs Kansas City Royals Prediction 06/30/2025 Picks

Pick details

Kansas City (39-45) vs Seattle (43-40)

June 30, 2025 at 09:40 PM EDT

The Line: Betting Odds: Seattle -160 / Kansas City +135 — Over/Under: +7.5

(Get latest betting odds)

The Kansas City Royals are visiting the Seattle Mariners on Monday, June 30th at the T-Mobile Park in the opening game of this series. We will look at this from a betting perspective and determine the best bets for this game. Here’s a Kansas City Royals vs Seattle Mariners Prediction. We will examine:
The Seattle Mariners recent form and player performance
The Kansas City Royals recent form and player performance
Recent betting trends and streaks involving the Seattle Mariners
Recent betting trends and streaks involving the Kansas City Royals
Recent betting trends in games played between the Kansas City Royals vs Seattle Mariners
A summary that ties it all together and produces a favorable betting outcome for the Kansas City Royals vs Seattle Mariners game

Seattle Mariners Preview

The Seattle Mariners have a 43-40 record this season and are sitting on the second place of the AL West. The Mariners have a 20-19 home record and 46-33 in over/under They are coming off a 6-4 road victory over the Rangers, and are 5-3 in their last 8 games. Over is 8-2 in their last 10 games and they are playing the Yankees and the Pirates next.

The Mariners have a .247 batting average this season, .324 OBP and .402 Slugging percentage. Seattle’s pitching staff has a 3.93 ERA and 1.28 WHIP. Julio Rodriguez leads the Mariners in hits with 88, while Cal Raleigh leads the team both in RBI with 69, and in home runs with 32. J.P. Crawford is the team’s best hitter with a .277 batting average.

George Kirby (R) is the projected starting pitcher for the Mariners, and he has a 1-4 record, 5.40 ERA and 1.28 WHIP.

Kansas City Royals Preview

The Kansas City Royals have a 39-45 record this season and are sitting on the third place of the AL Central. The Royals have a 19-21 road record and are 32-51 in over/under. They are coming off a 1-5 home defeat by the Dodgers, and are 1-7 in their last 8 games. Under is 7-1 in their last 8 games and are playing the Diamondbacks and the Pirates next.

The Royals have a .245 batting average this season, .299 OBP and .367 Slugging percentage. Kansas’ pitching staff has a 3.47 ERA and 1.21 WHIP. Maikel Garcia leads the Royals with 95 hits, and he is the team’s best hitter with a .314 batting average. Vinnie Pasquantino leads the team both in RBI, with 47, and in home runs, with 12.

Michael Wacha (R) is the projected starter for the Royals, and he has a 4-7 record, 3.33 ERA and 1.22 WHIP.

Why the Seattle Mariners will win

The Royals have lost each of their last eight night games against American League opponents that held a winning record.
The Mariners have won nine of their last 10 home games against the Royals.
The Royals have failed to cover the run line in six of their last seven games against American League opponents that held a winning record.
The favorites have covered the run line in three of the Mariners’ last four games at T-Mobile Park.
The Mariners have led after 3 innings in each of their last four games as favorites against AL Central opponents.
The Mariners have led after 5 innings in each of their last six games against the Royals at T-Mobile Park.

Why the Kansas City Royals will win

The Royals have won each of their last eight road games following a home loss.
The Mariners have lost each of their last six home games against American League opponents that held a losing record.
The Royals have covered the run line in each of their last 11 games as road underdogs following a loss.
The Mariners have failed to cover the run line in each of their last seven night games against the Royals following a road win.
The Royals have led after 3 innings in each of their last four road night games.
The Royals have led after 5 innings in each of their last six road games against AL West opponents.

Total Runs Facts

Seven of the Royals’ last eight games have gone UNDER the total runs line.
Six of the Mariners’ last seven games as favorites have gone OVER the total runs line.
The ‘Inning 1 UNDER 0.5 runs’ market has hit in eight of the Mariners’ last nine games against American League opponents.
The ‘Inning 1 UNDER 0.5 runs’ market has hit in 14 of the Royals’ last 16 games as road underdogs against AL West opponents.

Matchup/League Facts

The Mariners rank T28th in the league for triples this season (4).
The Mariners are one of only three teams in the league to rank top 10 in both steals and home runs this season.
The Royals rank 30th in the league for runs scored this season (277).
The Royals rank 30th in the league for home runs this season (58).

Kansas City Royals vs Seattle Mariners Prediction

The Mariners are 7-3 in their last 10 overall meetings against the Royals, and are 5-1 in their last 6 meetings in Seattle. Over is 7-3 in their last 10 meetings.    
In this Kansas City Royals vs Seattle Mariners Prediction, the Mariners are coming as -160 home favorites. The Mariners have a better overall record, but both teams have almost identical home/away splits. The Mariners have the better offense, they are playing the second straight series at home, while the Royals have to travel all the way from Kansas City. Kirby has been playing better for the Mariners lately, while Wacha has been weaker on the road for the Royals, who have been in terrible form. I expect the hosts to get the job done in this one, so take the Seattle Mariners on the moneyline.
 

Nikos Lagouretos's Pick: Seattle Mariners -160

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