Luis Castillo pitched six shutout innings, Jorge Polanco and J.P. Crawford drove in runs, and the Seattle Mariners beat the Kansas City Royals 2-0 on Thursday to move back into a first-place tie with the Houston Astros in the AL West.
The win set up a pivotal three-game series in Houston beginning Friday night, with both teams deadlocked in the standings.
Castillo (10-8) gave up just three hits, striking out six and allowing only one runner after the fifth inning.
The Royals managed singles in the second and third innings but stranded both.
Their only other hit came from rookie Carter Jensen in the fifth.
Castillo has now allowed only two earned runs across his last three starts.
On the other side, Kansas City starter Stephen Kolek (5-6) matched Castillo’s effort into the eighth inning. He gave up two runs, only one of them earned, and walked one.
Seattle struck first in the second inning when Josh Naylor singled and Polanco followed with an RBI double.
That 1-0 lead held until the eighth, when manager Dan Wilson’s challenge shifted momentum.
Kolek had what appeared to be the second out of the inning, but Wilson contested that Royals second baseman Michael Massey was positioned illegally on the infield grass for Dominic Canzone’s grounder.
The review confirmed the violation of Major League Baseball’s defensive shift rules, putting Canzone on first base.
Reliever Daniel Lynch IV replaced Kolek and gave up a run-scoring double to Crawford, giving Seattle insurance with a 2-0 lead.
Eduard Bazardo and Gabe Speier each pitched a scoreless inning in relief before Andrés Muñoz closed the ninth.
Muñoz worked around two baserunners and struck out Adam Frazier on three pitches for his 36th save.
Seattle heads to Houston on Friday with right-hander Bryan Woo (14-7, 3.02 ERA) set to start the opener of the three-game series.