Seattle Mariners
Kansas City Royals
(-110/-110)+100
As the Kansas City Royals prepare to host the Seattle Mariners on September 18, 2025, both teams find themselves in different places in the standings. The Mariners, with an 83-69 record, are enjoying an above-average season, while the Royals sit at 76-76, reflecting an average year. This matchup is crucial for the Mariners as they look to solidify their postseason positioning.
In their previous game, the Mariners secured a win against the Royals, showcasing the strength of their offense, which ranks 11th in MLB. The Mariners’ power has been evident this season, as they lead the league with 223 home runs, presenting a significant challenge for Royals’ starter Stephen Kolek. Although Kolek has a respectable ERA of 3.71, advanced metrics suggest he could be due for a regression, as his 4.26 xFIP indicates he may have benefitted from some luck.
Luis Castillo, projected to start for the Mariners, has had a solid season as well, with a 3.76 ERA. While he has been regarded as an average pitcher overall, the projections suggest he has the potential to perform well against a Royals lineup that ranks 24th in MLB offensively. This season, Kansas City has struggled to generate runs, particularly in the power department, ranking 25th in home runs.
The Royals’ best hitter has been on a tear lately, boasting a 1.000 batting average and a 2.050 OPS over the past week, which could provide a glimmer of hope against Castillo. However, with the Mariners’ bullpen ranked 13th and the Royals’ bullpen at 21st, the Mariners may have the edge in late-game situations.
With a Game Total set at 9.0 runs, this matchup promises to be competitive, especially considering the close moneyline odds. The Royals have an implied team total of 4.34 runs, while the Mariners sit at 4.66, indicating expectations for a high-scoring affair.
Seattle Mariners Insights
- Luis Castillo – Over/Under 4.5 Strikeouts (+130/-165)Luis Castillo’s higher utilization rate of his fastball this year (68.7 vs. 63.4% last year) is not ideal consider they are generally much less effective than breaking or off-speed pitches.Explain: Fastballs are the one easiest pitches to hit and generate few strikeouts, so a pitcher who begins to use his fastball more often will likely be less effective than he used to be.
- J.P. Crawford – Over/Under 0.5 Hits (-190/+145)J.P. Crawford has primarily hit in the top-half of the batting order this season (52% of the time), but he is penciled in 9th in the batting order in this matchup.Explain: The lower in the order a player bats, the fewer plate appearances he will get and the fewer opportunities he will get to hit the Over for every market. A player who hits lower in the order than he normally does may provide extra value opportunity since the market may be based on him hitting higher.
- The 9.6% Barrel% of the Seattle Mariners grades them out as the #7 club in Major League Baseball this year by this stat.Explain: Barrel% measures how often a player hits the ball at the optimal exit velocity and launch angle and is a terrific measure of underlying power.
Kansas City Royals Insights
- Stephen Kolek – Over/Under 3.5 Strikeouts (-115/-115)Stephen Kolek’s 2184-rpm fastball spin rate this year is in the 24th percentile out of all starters.Explain: Spin rate is a key component to fastball success in generating strikeouts and preventing runs.
- Michael Massey – Over/Under 0.5 Total Bases (-155/+120)Michael Massey’s average exit velocity has fallen off lately; his 86.6-mph seasonal average has dropped off to 79.6-mph in the past two weeks.Explain: Hitting the ball hard increases the chances of either a home run or the ball landing in fair territory for a hit before a fielder can get to it.
- Jac Caglianone – Over/Under 0.5 Total Bases (-180/+140)Jac Caglianone hits a lot of his flyballs to center field (39.6% — 95th percentile) and has the misfortune of hitting them towards the league’s 4th-deepest CF fences in today’s matchup.Explain: This player’s skill set does not match up particularly well with the park he’s in today, which may lead to worse-than-usual performance.
Betting Trends
- Kansas City Royals – Over/Under 4.5 Team Total (+110/-140)The Kansas City Royals have hit the Team Total Under in 90 of their last 149 games (+25.55 Units / 15% ROI)
- Over/Under 9.0 Game Total (-110/-110)The Seattle Mariners have hit the Game Total Over in 83 of their last 152 games (+13.85 Units / 8% ROI)
- Julio Rodriguez – Over/Under 0.5 Home Runs (+460/-750)Julio Rodriguez has hit the Home Runs Over in 4 of his last 10 away games (+13.20 Units / 132% ROI)