Mariners vs Royals Prediction 9/18/2025 Today’s MLB Picks

In this article we will formulate a Mariners vs Royals prediction for this MLB game on Thursday, September 18th at Kauffman Stadium in Kansas City, Missouri. Let’s take a look at the prediction for this MLB matchup. 

Seattle Mariners Betting Preview

The Seattle Mariners are 83-69 this year after they split the first two games in this series by scores of 12-5 and 5-7. In their game two loss, Seattle led 4-3 in the eighth inning, but allowed four runs in the eighth for the defeat. The Mariners recorded 10 hits and they committed one error in the game, while they were led by Suarez, who went 4-4 with one home run and two RBIs in the loss. Seattle started Miller, who allowed eight hits and three earned runs over 5.0 innings, while Brash blew the save and picked up the loss. 

Prior to this series, the Mariners won all four against the Angels and all three against the Cardinals. Seattle has won 10 of their last 11 games and they are second in the AL West standings. The Seattle pitching staff has a 3.94 ERA with a 1.24 WHIP and a .243 opponent batting average, while the offense has scored 722 runs with a .245 batting average and a .321 on base percentage this season. Cal Raleigh has led Seattle with 56 home runs and 118 RBIs, while Julio Rodriguez has added 30 home runs and 93 RBIs this year. The projected starting pitcher for Seattle is Luis Castillo, who is 9-8 with a 3.76 ERA and a 1.25 WHIP over 167.1 innings pitched this year. 

Kansas City Royals Betting Preview

The Kansas City Royals are 76-76 this season after they won game two by a score of 7-5 on Wednesday night. Kansas City led 3-0 in the first inning, but they needed a late rally in the eighth to escape with the victory. The Royals recorded 13 hits in the game and they were led by Perez, who went 1-2 with one home run and three RBIs in the win. KC started Ragans, who allowed one hit and two earned runs over 3.2 innings, while Erceg got the win and Estevez picked up the save. 

Prior to this series, the Royals lost two out of three against the Phillies and three out of four against the Guardians. Kansas City has lost seven of their last ten games and they are third in the AL Central standings. The Kansas City pitching staff has a 3.79 ERA with a 1.26 WHIP and a .244 opponent batting average, while the offense has scored 589 runs with a .245 batting average and a .306 on base percentage this season. Vinnie Pasquantino has led KC with 30 home runs and 104 RBIs, while Salvador Perez has added 29 home runs and 92 RBIs this year. The projected starting pitcher for Kansas City is Stephen Kolek, who is 5-5 with a 3.71 ERA and a 1.20 WHIP over 99.1 innings pitched this season. 

Why the Royals will beat the Mariners 

The Mariners have lost five of their last six games as road favorites against American League opponents following a road loss.
The Royals have won eight of their last 10 games as underdogs against AL West opponents following a home win.
The Mariners have failed to cover the run line in nine of their last 10 road games against American League opponents after playing the previous day.
The Royals have covered the run line in eight of their last 10 games against AL West opponents that held a winning record.
The Royals have led after 3 innings in seven of their last nine games against AL West opponents that held a winning record.

Why the Mariners will beat the Royals 

The Mariners have won each of their last nine games as favorites.
The Royals have lost 10 of their last 12 home games against American League opponents that held a winning record.
The Royals have failed to cover the run line in six of their last seven games at Kauffman Stadium following a win.
The favorites have covered the run line in eight of the Mariners’ last 10 games.
The Royals have trailed after 3 innings in three of their last four games as underdogs against American League opponents.
The Mariners have led after 5 innings in each of their last four games as favorites against American League opponents.

Total Runs Facts

Eight of the Mariners’ last nine games against American League opponents have gone OVER the total runs line.
Each of the Royals’ last five games have gone OVER the total runs line.
The ‘Inning 1 OVER 0.5 runs’ market has hit in each of the Royals’ last eight games as underdogs.
The ‘Inning 1 OVER 0.5 runs’ market has hit in each of the Mariners’ last four games.

Kansas City Royals Player Prop Facts

Salvador Perez has hit at least one home run in three of the Royals’ last four games against opponents that held a winning record.
Michael Lorenzen has recorded five or more strikeouts in four of his last five appearances against the Mariners.
Bobby Witt Jr. has recorded at least one hit in each of the Royals’ last nine games against the Mariners.

Seattle Mariners Player Prop Facts

Julio Rodriguez has recorded at least one Double in five of the Mariners’ last six games as favorites.
J.P. Crawford has hit a home run in three of the Mariners’ last four road games against the Royals.
Jorge Polanco has recorded at least one hit in each of the Mariners’ last 11 games as favorites.

Mariners vs Royals Prediction 

Seattle had their winning streak snapped on Wednesday night in game two of this series and they dropped to second in the AL West standings. The Mariners are 35-42 on the road this year, while the Royals are 41-36 at home. Kansas City has won two of their last three games and they are starting Kolek, who has allowed two earned runs or fewer in three straight starts. Seattle is going with Castillo, who has allowed one earned run in back to back outings. I like this pitching matchup and I think we are going to see a lower scoring game. Take the under here.