Your Most Valuable Brewers' Batter is ... Keston Hiura?

The human mind can only remember and track so much, maybe somewhat mercifully. But humankind has found ways around that, with the most recent method being computers.

One sabermetric statistic, Win Probability Added (WPA), would be entirely impossible without computers, because it tracks and sums up players’ contributions on individual at-bats. You can’t look at a player’s stat line and figure out WPA. You have to go through each at-bat, determine how much they contributed or degraded their team’s chances of winning, and add them all up together.

WPA is unique and interesting because it reflects how much a hit or out actually counted in the result of the game. A 2-run home run by a player whose team is down 11-2 in the bottom of the ninth doesn’t make much difference, and thus doesn’t mean much in terms of WPA. The same home run when down 5-4 is huge and rewarded with tons of WPA points.

How does that work? If you would like dive into how it works, check out the extra notes at the end of the story. I assure you, it’s very straightforward math.

WPA, like any stat, also its weaknesses. But one of its strengths is that it is good at seeing which players made big differences, both positive and negative, both  in individual games and cumulatively throughout a season. It is good at seeing which players rose above or sunk below their stat line to impact wins and losses. So it's a very cool statistic when determining which player was the most valuable for their team. 

Which brings us to Keston Hiura, of all people. Among Brewers’ batters, Hiura has been a difference maker in Milwaukee’s games, and it’s not particularly close. Second place belongs to Rowdy Telez and Christian Yelich with a WPA of 0.9. Hiura clocks in at 1.4, pretty much a full win more than either of them.

That’s because he’s had some huge games, powered by some huge hits. Here are four games, all of which featured a big Hiura hit in bottom of the ninth or later:

#4 -  8/29 vs PIrates (WPA 0.29)
With the Brewers fighting for their postseason lives, he homered off of Pirates’ Will Crowe to break a 5-5 tie and win the game for the Brew Crew. Let’s have a look at that:

#3 – 7/4 vs Cubs (WPA 0.33)
Also in the ninth, down 2-1 and facing a mostly unhittable David Robertson, Hiura doubled to deep center field to set up a game-tying walk by Yelich in a game the Brewers won over the Cubs in extra innings.

#2 – 8/7 vs Reds (WPA 0.44)
His leadoff solo home run in the bottom of the ninth tied the game at 2-2 to take the game to extra innings. The Reds won the game in the 10th, but that meltdown counted against Devin Williams’ WPA. Hiura did his part.

#1 – 5/18 vs Braves (WPA 0.56)
In the bottom of the 11th, Hiura hit a 2-run leadoff home run to overcome a 6-5 deficit and walkoff Atlanta. Mayhem ensued.

To be fair, Hiura has also had 32 games with a negative WPA, but that’s to be expected for hitters. They're expected to fail, so most of their at-bats end up with a negative WPA. The big hits are what get them a high score. (Pitchers are the opposite. A big blown save kills their WPA. Every successful holds or shutout innings adds a little back.)

But the math behind WPA is clear (and again, below). It tells us that when we add all those plate appearances up, Hiura has had a season that other Brewers batter should rightfully envy.

However, there are currently a couple of pitchers on the Brewers' pitching staff that exceed his impact this year. We’ll cover them next time. 

Win Probability Added tracks what it says it tracks: how much a pitcher and batter add to (or subtract from) their team’s probability to win the game. Let’s do a quick example from Tuesday’s 8th inning meltdown to see WPA in action.

Things had gotten dicey in the eighth inning. Luis Perdomo had given up a big homerun to Yonathan Daza to make the score 6-5. So Peter Strzelecki entered the game with the Brewers having a 65% chance to win. He struck out CJ Cron and that raised the chances to win to 72%, a difference of 7%. So Strzelecki gains .07 WPA and Cron loses .07 WPA.

Getting Charlie Blackmon to fly out raises the Brewers’ chances to 77%, an increase of 5%, so Strzelecki gains another .05 and Blackmom loses .05. But when Randal Grichuk went yard to tie the game, the Brewers’ chances of winning sunk to 47%, a decrease of 30%. Strzelecki loses .30 WPA and Grichuk gets .30.

So the final totals for WPA for those players over those 3 at-bats are:

• Strzelecki = -.18 WPA (+0.07+0.05-0.30)
• Cron = -0.07 WPA
• Blackmom = -0.05 WPA
• Grichuk = +0.30 WPA