Yordan Alvarez's Game-Winning Three-Run HR Was Most Impactful Offensive Play In Postseason History

Yordan rules. #Postseason pic.twitter.com/yaQAKx8bFw

— MLB (@MLB) October 11, 2022

Mariners - 130 200 100 - 7 13  0
Astros   - 001 200 023 - 8 11  0

Mike Petriello (MLB.com) reports that Yordan Alvarez's ninth-inning, game-winning three-run homer, which gave the Astros an 8-7 win over the Mariners on Tuesday in ALDS Game 1, "the most valuable postseason moment a position player has ever had", as measured by Win Probability Added.

When Alvarez stepped to the plate in the ninth inning, Seattle's win probability was 91%. That's based on the history of road teams who were ahead by two runs with two outs and two on in the ninth inning, as the Mariners were. . . .

If Seattle's odds were 91% when the pitch left Robbie Ray's hand, then by the time Alvarez's blast landed 438 feet away, their odds of winning were 0%, because the game was over. Houston was at 100% – again, the game was over! – up from 9%. Just look at the chart. You get the idea. Look at that absolute cliff at the end.

The way win probability works, Alvarez gets credit for the 91%. If you go pull up the list of the most important postseason plays in history in terms of winning that specific game … ladies and gentlemen, we have a new No. 1.

+91% – Yordan Alvarez, Astros, Home run, ALDS Game 1, 2022
+87% – Kirk Gibson, Dodgers, Home run, World Series Game 1, 1988
+83% – Jimmy Rollins, Phillies, Double, NLCS Game 4, 2009
+83% – Brett Phillips, Rays, Single, World Series Game 4, 2020
+83% – Cookie Lavagetto, Dodgers, Double, World Series Game 7, 1947

Every other player on this list had their team down by one run with two outs, not two runs; every other team that had odds so low came back with multiple plays, not one. As MLB.com's Sarah Langs noted, there had been only four walk-off homers when trailing in postseason history, and only two of those four came with two outs, and only Alvarez's also came while behind multiple runs. He now stands alone in history.

Alvarez was also responsible for the second-most impactful play of the game. His two-run double in the third inning cut Seattle's from 4-0 to 4-2, improving the Astros's chances of winning from 15% to 30%, so he gets credit for 15% on that play.

Alvarez also threw out a runner at the plate, cutting a Seattle rally short and ending the fourth inning – but WPA concerns hitters only. The Mariners' fourth inning went: K, K, HR, 3B, 2B, 1B. (A downward cycle?)

Add up (or subtract) the differences in Win Probability Added before and after each of Alvarez's five plate appearances –

B1: P5         -  1%
B3: Double     + 15%
B5: 4-3        -  1%
B8: Single     +  2%
B9: Home Run   + 91%

– and he finished with a WPA of +105.4%, the highest total in postseason history. (Those numbers add up to 106%, so they must be rounded up or down.)

+105.4% – Yordan Alvarez, Astros, ALDS Game 1, 2022
+ 96.4% – David Freese, Cardinals, World Series Game 6, 2011
+ 87.0% – Kirk Gibson, Dodgers, World Series Game 1, 1988
+ 85.4% – Steve Garvey, Padres, NLCS Game 4, 1984

How can a player's WPA be more than 100%? Petriello explains:

[W]in probability can go up and down as a game goes along . . . many other Astros (notably starter Justin Verlander, who allowed six runs in four innings, and batters Jose Altuve and Trey Mancini, who combined to go 0-for-9 with a walk) were a net negative towards Houston winning this game. Alvarez didn't just have to perform his own heroics. He had to overcome the hole the Astros placed themselves in to get there.

Jayson Stark had a bunch more Starky stuff on the day's events.

Astros fan @Matthew_Mintz1 video of Yordan Alvarez’s historic home run. You can hear one fan say ‘imagine if Yordan hits a home run.” pic.twitter.com/k4AbnIHZNa

— Mark Berman (@MarkBermanFox26) October 12, 2022