Opening Day, April 1, 2013 is 34 days away. There have been one hundred walk off home runs in Angels history. This is the story of #34, the greatest day on offense by an Angels player comes against the Yankees.
July 15, 1979 - This Sunday afternoon game was the climax of a three game sweep of the Yankees. Bobby Grich hit a walk off home run to cap the the single game record for best offensive performance in Angels history.
How does one measure the best offensive performance in a game? Garret Anderson once had ten RBI in a game, but most of them came after the Angels were way ahead - Since the Angels were already quite likely to win the game, one could argue that Garret's at-bats came in situations that were less important then other instances in other games when a player gets a clutch hit to come back from a a deficit, tie the game and /or go ahead. Even these walk off home runs are not all created equal. Hitting a walk off grand slam in a tie game with nobody out is not as impressive or impactful as hitting one down by three runs with two outs.
A stat has been developed to measure the impact of each play in a game. WPA stands for Win Probability Added. Starting each game as a 50/50 proposition, WPA measures each play in the game as adding or subtracting from a win. In this game, Bobby Brown (the Yankees CF, not the singer) led off the game with a ground out. The Angels then had a 52% chance of winning the game and the Yankees a 48% chance. The second batter, catcher Thurman Munson, singled. the probability of each team winning was then back to 50/50 - a man on first with one out in the top of the first gives each team the same chance of winning as if the game had begun. The third batter of the game, Chris Chambliss, hit a two-run homerun off Angels starter Dave Frost. The Homerun gave the Yankees a Win Probability Added of 17%. Suddenly the Angels only had a 33% chance to win the game.
WPA is added to individual players based on what they accrued. At this juncture in the game Thurman Munson had a .020 WPA and Chris Chambliss had a .170 WPA. Meanwhile Starter Dave Frost had a negative WPA of -.660 at this point in the game.
The best news for fans of Angels WPA is that being down by two runs early gives every positive batter's box action by an Angel a bigger percentage of of positive WPA. But in the top of the second inning, Dave Frost gave up another two run hoe run. The problem with WPA is that a big hit has less impact when your team is down by a lot. The hill you have to climb seems even bigger when a two out single only increases your team's chances of winning by 1%, as Merv Rettenmund's single in the bottom of the second inning did. And sure enough, Ron Guidry got the next batter o end the inning and underscore the pointlessness of that hit. Sad, eh?
But Bobby Grich did something about it all. In the bottom of the third inning, Bobby Grich singled in Jim Anderson to make it 4-1. His WPA on the play was .080 - His RBI had increased the Angels chances of winning the game by eight percent.
In the bottom of the seventh, Grich doubled in Anderson and Rick Miller. 4-3 Yankees. Add .220 to his personal WPA. The Angels likelihood of winning the game at this juncture was now 40%, up from a low of 10% when Guidry struck out Willie Mays Aikens to end the sixth inning.
Guidry was still on the mound in the ninth inning with two outs. Jim Anderson had flown out and Guidry walked catcher Tom Donohue ahead of striking out Rick Miller.
It was then Bobby Grich versus Ron Guidry for the game. A two out, two-run, come from behind walk off home run sealed the game for the Angels and completed the weekend sweep to let the rest of the baseball world that these Angels were for real.
Final Score: Angels 5, Yankees 4. The Walk Off Home Run increased the Angels chances of winning the game from ten percent to 100%. Add the .900 to Grich's WPA for the day and you get a single game franchise record WPA of 1.211... an amazing afternoon in a season that transformed what it meant to be an Angels fan.