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Back on April 11, with the Detroit Tigers trailing 3-2 in the top of the seventh inning, Indians manager Terry Francona called on lefty reliever Marc Rzepczynski to face Alex Avila. Brad Ausmus countered the move by pinch-hitting with his right-handed backup, James McCann, who hit a ground ball single through the left side. With one out, Andrew Romine worked a five-pitch walk, moving McCann into scoring position and opening the door for a trio of singles from his more highly renowned teammates, and a 5-3 Tigers lead.
Win Expectancy (WE) is a statistic that estimates a team’s likelihood of winning a game in any conceivable situation. At the start of a game, both teams’ WE is roughly 50 percent, and it will increase or decrease as events unfold within the game. When a player makes an out, his team’s WE will go down, and when he gets on base, it will go up. The fewer innings remaining in a game, and the closer the score, the more impact an event will have on WE.
When Romine came to the plate in the seventh, the Tigers had a 15.9 percent chance of winning. After his walk, the WE bumped up to 22.1 percent for a 6.2 percent increase. This increase is also known as Win Probability Added (WPA), a stat that tracks the impact a player has within the context of the games being played. While most advanced metrics focus on stripping away the context to more accurately evaluate an individual’s true abilities, WPA focuses on what actually happened in a team environment. You can see how the win probability fluctuates throughout a game in the charts that we post at the bottom of every game recap:
Source: FanGraphs
But the two-run lead that Romine helped build wouldn’t stick, as Ian Krol and Al Alburquerque teamed up to allow a pair of walks and a two-run double in the eighth inning. Romine led off the ninth, this time batting from the left side against the righty Cody Allen, and worked another base on balls. He managed to steal second base on the fifth pitch of the next at-bat, a huge advantage in the ninth inning of a tie game. Ian Kinsler followed with a line drive single, the Tigers taking the lead when Romine crossed plate, and would go on to win 9-6.
This time, the Tigers’ WE increased from 47.8 percent to 56.4 percent with Romine’s walk, and then to 65.6 percent after he moved himself in scoring position. Earlier in the game, Romine had hit a single, stolen another base, and drawn a third walk. While these earlier plays didn’t swing the likely outcome of the game as much as his late-game walks, his total WPA was 0.251, an impressive figure considering a fairly pedestrian line of 1-for-2 with three walks (this could also be a post about how walks and steals are largely undervalued, but it’s not).
But that wouldn’t be the only time Romine would quietly impact a Tigers’ win. On April 29th he would post a 0.282 WPA when his RBI single in the eighth inning broke a tie with the Minnesota Twins. On May 10th against the Royals, a 10th-inning single and wild pitch propelled him to a 0.211 WPA. And on June 23rd, a home run and a double off of Danny Salazar resulted in a 0.195 WPA.
Of course, WPA can cut the other way as well. When a player has a bad day and hurts his team’s chances to win, he’ll post a negative WPA. Romine’s best example came on June 17th, when he posted a -0.140 WPA after taking over for Nick Castellanos as a defensive replacement. Joba Chamberlain allowed the game-tying run to score, and Romine would end up getting two important at-bats, striking out in both. However, WPA is accumulated from each game, and Romine has contributed far more positive than negative over the course of the season.
WPA | +WPA | -WPA | |
Miguel Cabrera | 2.75 | 7.29 | -4.54 |
Andrew Romine | 0.76 | 1.84 | -1.08 |
J.D. Martinez | 0.38 | 6.39 | -6.01 |
Alex Avila | 0.37 | 1.55 | -1.18 |
Yoenis Cespedes | 0.24 | 6.64 | -6.39 |
Anthony Gose | 0.24 | 4.34 | -4.10 |
As you would expect, Miguel Cabrera leads the team in yet another offensive stat, and he leads by a terrific margin. Another unsurprising name is found near the top of the list in J.D. Martinez, whose WAR figure recently surpassed that of Cabrera’s, coincidentally. The surprise here is Romine (well, and maybe Alex Avila), who has managed to accrue more WPA in a mere 82 plate appearances than any other human Tigers hitter.
Most Tigers’ fans will recognize that Romine has been hitting well this season, but few would advocate that he has turned the proverbial corner. His .320 batting average has been a pleasant surprise, but in his scant playing time it doesn’t seem to hold much weight, and no one expects it to continue. Romine is certainly a valuable player, but his value comes mostly in his ability to fill a relatively unimportant role. Although, according to WPA, he’s actually been the second-most valuable Tigers hitter in 2015.