MLB Recap · September 15, 2023

Houston Astros at Kansas City Royals: Final Score & Recap

HOU2
Final
KC4

Line Score

Team123456789RHE
HOU000001001270
KC00111001-491

The Story

The Kansas City Royals defeated the Houston Astros 4-2 at Kauffman Stadium on September 15, 2023, a result that the DiamondIQ model's estimate reflected sharply as pregame home win probability sat at just 30% before climbing to a certainty of 100% by the final out. The Royals built their margin incrementally, plating single runs in the third, fourth, fifth, and eighth innings, while Houston managed to answer only in the sixth and ninth, never stringing together enough to seriously threaten.

The game's most decisive sequence came in the bottom half of the middle innings, where Kansas City's offense did its damage against Cristian Javier. Nelson Velazquez launched a home run in the fourth inning, a swing that shifted win probability by 10.5 percentage points in the Royals' favor, and Bobby Witt Jr. followed with another solo shot in the fifth, adding another 9.1 percentage points. Those back-to-back blows off Javier effectively separated the two clubs. Houston's best chance to close the gap came in the sixth, when Yordan Alvarez laced a double off Angel Zerpa that generated a 12.8-point swing, but the Astros were unable to capitalize fully on that momentum. Alex Bregman then buried Houston's hopes in the eighth, grounding into a double play against Carlos Hernandez that cost the Astros 13.8 percentage points of win probability.

Witt finished as the game's top performer by run environment impact with a RE24 of plus-1.1, while Velazquez and Alvarez each posted plus-1.0, though Alvarez's individual WPA of plus-16.3 led all batters in either lineup. On the pitching side, Zack Greinke contributed the most to Kansas City's cause with a WPA of plus-15.0, followed by Zerpa at plus-13.9 and Hernandez at plus-8.1, a trio that collectively held Houston to a line of seven hits and no errors across nine innings.

Analysis generated by DiamondIQ's model.

Win Probability

755025HOU bats firstFinalKC win %HOU win %
DiamondIQ model home win probability across the game (pre-game 30% → final 100%).

Biggest Plays by Win-Probability Added

Alex Bregman Grounded Into DP
Top 8th · off Carlos Hernández
-13.8%
Yordan Alvarez Double
Top 6th · off Angel Zerpa
+12.8%
Nelson Velázquez Home Run
Bot 4th · off Cristian Javier
+10.5%
Jose Altuve Forceout
Top 2nd · off Zack Greinke
-10.0%
Bobby Witt Jr. Home Run
Bot 5th · off Cristian Javier
+9.1%

Top Batters by WPA

Yordan Alvarez+16.3%+1.0 RE24
Bobby Witt Jr.+13.1%+1.1 RE24
Nelson Velázquez+10.9%+1.0 RE24

Top Pitchers by WPA

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