Adam Frazier hit a go-ahead, two-run home run in the eighth inning and the Kansas City Royals beat Seattle 7-5 to snap the Mariners’ 10-game winning streak.

A strange rule violation ended up playing a key factor in why the Kansas City Royals narrowly lost their Thursday afternoon contest to the Seattle Mariners.

The Kansas City Royals grabbed a 7-5 victory over the Seattle Mariners, stopping their winning ways and dropping them to second place in the American League West

View news about the Seattle Mariners vs. Kansas City Royals game played on September 17, 2025 including player news, injury news, predictions, analysis and more.

The Seattle Mariners are sticklers for the new shift rule. As the Mariners faced he Kansas City Royals on Thursday, Royals' second baseman Michael Massey lined up with his heels slightly touching the outfield grass, which is technically illegal with the new rule implemented this season.

The Seattle Mariners are tied with the Houston Astros for the AL West lead with a pivotal three-game series between the two teams set to begin Friday night at Daikin Park.

Preview the Sept. 18 matchup between the Seattle Mariners and Kansas City Royals with odds over/under, game spread, betting lines and more.

Following their ten-game winning streak being snapped by the Kansas City Royals on Wednesday, the Seattle Mariners came firing back in the final game of the tea

The Mariners needed to escape Kansas City with a series win, and they did. But all it got them was back to square one.