Luis Robert Jr., a bright spot in a rough White Sox season, has been getting results worthy of his quality of contact.
The same goes for Jake Burger in more limited play. Yoan Moncada, on the other hand, has numbers far better and Tim Anderson far worse than their contact would seem to support.
Statcast data at baseballsavant.mlb.com includes expected stats, using launch angle, exit velocity and sometimes the batter’s sprint speed.
One category is expected weighted on-base percentage (xwOBA). Much like weighted runs created plus, wOBA weighs each offensive event from home runs through double plays to give a more complete measure of offensive value than batting average or other narrowly focused stats can yield.
Robert’s offensive game has been stellar. Hitting .275/.335/.562 with 11 home runs, he ranks 29th among major-league qualifiers with a .377 wOBA. His xwOBA is roughly at the same level, .366.
Coupled with strong center-field defense, Robert’s production has made him one of the most valuable players in baseball so far in 2023. His 1.7 wins above replacement at Fangraphs rank 14th in the majors.
The basic formula for wOBA, as explained at Fangraphs.com, is wOBA = (0.690×unintentional BB + 0.722×HBP + 0.888×1B + 1.271×2B + 1.616×3B + 2.101×HR) / (AB + BB - intentional BB + SF + HBP). Weights change slightly each year, depending on current offensive environment. So far in 2023, the multiplier for singles is .889 instead of .888, with 1.256 for doubles, 1.586 for triples and 2.031 for home runs.
The major-league average for wOBA is .318 in 2023 after .310 last season and .314 in 2021.
Burger, hitting .239/.321/.648 with eight home runs, has packed power into his 81 plate appearances. His .400 wOBA is just below his .408 expectation. If he kept that pace through enough plate appearances to qualify, his wOBA would rank among the top 15 in the majors.
Moncada, back from injury, has 52 plate appearances and a stellar .370 wOBA, but his quality of contact suggests a more normal level would be .277.
His small sample has brought much more success than is usual when 64.9% of batted balls are grounders and only 13.5% are line drives. In 2021, when Moncada had a .347 wOBA, 26.6% of his batted balls were liners and 43.8% were on the ground. In 2022, when he fell to a .275 wOBA, line drives collapsed to 17.3%.
Anderson has been a ground-ball hitter through most of his career. His 64.5% of batted balls on the ground is up from 54.9% last season and 52.3% in his career, but he’s hitting the ball hard. Baseball Savant says 50% of his batted balls have had exit velocities of at least 95 mph. His hard-hit percentage ranks 32nd in the majors.
Nonetheless, Anderson is hitting only .260/.304/.313. His batting averages since 2019 have been .335, .322, .309 and .301, with wOBAs of .363, .376, 345 and .322.
A .277 wOBA is a comedown, but Statcast’s xwOBA says Anderson’s contact has had the quality of a .325 xwOBA.
If Anderson’s quality of contact continues, his numbers will improve. If Robert’s continue at his level, he’s a star.
