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 we're looking for downsides when it comes to Chapman, there are a few. For starters, hitters have adapted to Chapman quite well over the years, after posting chase rates of over 30% from 2015 through 2018, and another three seasons of over 25% from 2019 through 2021, the soon to be 36-year old has seen his chase rate drop to 22.5% and 23.4% over the last two seasons, which according to Baseball Savant ranks in the bottom 5% in baseball.

On top of the lower chase rates, Chapman still has quite a bit of a wild side, walking 14.5% of batters faced in 2023. In 58.1 innings pitched, he walked 36. His walk percentage was the third straight season in which he walked over 14% of batters faced. In his previous six seasons, he had posted just one season of walking 14% or more of all batters faced. Of all his concerns, this is arguably the most concerning.

Then there is the conundrum of being a power pitcher. Despite recording an expected slash of .171/.258/.277 against Chapman recorded a barrel percentage of 9.2%, the third highest of Chapman's career, an average of one barrel for every four at-bats.

Finally, there's the arguably the obvious concern.


Yes, Chapman posted quality numbers and very good advanced stats at 35 last year but every additional year makes it a little harder to meet those numbers. Can Chapman at age 36 continue to be a dominant reliever? As a power pitcher, if Chapman sees a dip in his velocity, it could be a season that goes south quite quickly.

That being said, there was no sign that his age was affecting him last season from a stuff perspective. The fastball is still there and the velocity is still very good. Last season, Chapman's fastball averaged 99.0 miles per hour and his sinker still touches 100 and 101 on a routine basis. He may not be throwing 103, 104, 105 like he did as a young 22-year-old with Cincinnati back in the 2010s but he still showed plenty of juice in his arm in 2023.

Notably, as last season went on for Chapman, he did have a few struggles including a six game stretch from August 21 to September 2 in which he pitched in six games, allowing five earned runs and seven total in 5.2 innings pitched. During that stretch he walked seven, hit one batter, and gave up five hits including two home runs.

Following that tough stretch, he finished the season allowing four earned runs in his last eight games pitched.

After the ups and downs of August and September, Chapman had a strong postseason for the Rangers, allowing just two earned runs across nine games and eight innings pitched.