Pittsburgh Pirates: Possible Expectations for Aroldis Chapman

The Pirates made a big splash by signing Aroldis Chapman on Monday but what should the expectations be for the flamethrowing lefty?
World Series - Texas Rangers v Arizona Diamondbacks - Game Five
World Series - Texas Rangers v Arizona Diamondbacks - Game Five / Christian Petersen/GettyImages
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If one were to look at Chapman's Baseball Savant page, one would be quick to see that the Cuban lefthander is still among the best relievers in baseball from an advanced stats perspective. Of the 12 advanced statistics that Baseball Savant includes in their percentile rankings, Chapman was in the top 5% of the league in six categories; expected batting average, expected slugging, weighted on-base percentage, expected weighted on-base percentage, strikeout percentage, and expected era.

Against Chapman in 2023, hitters posted an expected slash line of .171/.258/.277. They also struck out 41.4% of the time, which ranked second among all relievers last season who recorded 50 or more innings pitch. The only reliever with a higher strikeout percentage was Baltimore's All-Star closer Felix Bautista at 46.4%.

The 6-foot-4, 235-pound Chapman also still records some of the highest whiff rates in all of baseball. In 2023, he recorded a whiff percentage of 42.2%, the third highest in baseball last season among all pitchers only behind the aforementioned Bautista and newly signed Los Angeles angel Robert Stephenson.

The expected batting averages and expected slugging percentages of opossing batters both ranked top 10 in baseball among both starters and relievers

Finally, despite posting a high barrel rate in 2024 (more on that below), Chapman is still posting a strong average exit velocity on batted balls. Last season, batted balls off Chapman averaged out at 86.5 mph which ranked 50th in baseball among 443 pitchers who faced 150 or more batters in 2023.

These of course are just a few highlights of Chapman's 2023 advanced stats. Other numbers to know include his 33% hard-hit rate percentage which ranked in the 87th percentile of all pitchers and his 47.7% ground ball rate which was in the 76th percentile of all pitchers.