Philadelphia Phillies star outfielder Bryce Harper put together a strong offensive campaign in the pandemic-shortened 2020 season. He hit .268 with 24 extra-base hits, a .960 OPS, and a 159 OPS+, which is 59 percent above league average.
But what if I told you that Harper’s actual stats don’t paint a clear picture of how well he hit the ball last season, and that he’s due for a monster 2021?
Expect big numbers from Phillies star Bryce Harper in 2021.
After sifting through Harper’s ‘expected outcome’ data on Statcast from last season, it’s clear that the 2015 National League MVP was the victim of some unfortunate luck at the dish. Let’s first set the scene with what we’re looking at and why we’re doing it.
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It’s widely accepted that a line-drive hit right at a fielder is more encouraging than a jam-shot blooper that finds the outfield grass for a single. Sure, one is an out and one is a hit, but that’s where ‘expected outcome’ data (explained below in Statcast‘s own words) becomes such a useful tool.
"Expected Outcome stats help to remove defense and ballpark from the equation to express the skill shown at the moment of batted ball contact. By looking at the exit velocity and launch angle of each batted ball, a Hit Probability is assigned based on the outcomes of comparable historic balls in play. By accumulating the expected outcomes of each batted ball with actual strikeouts, walks and hit by pitches, Expected Batting Average (xBA), Expected Slugging (xSLG), and (most importantly) Expected Weighted On-Base Average (xwOBA) tell the story of a player’s season based on quality of and amount of contact, not outcomes."
Over time, there’s a greater likelihood that a ball smoked off the bat will lead to more hits than outs, and a weakly hit ball that finds a hole will lead to more outs than hits. These predictive statistics don’t tell the whole story, but they tell some of it, and it gives us added context, in this case, into how well a player is hitting the ball, despite his results. The key phrase from the above quote: “quality of and amount of contact, not results.”