Former Royals fireballer plays key role in big Red Sox season

The Boston Red Sox scored a heart-pounding, 4-3 walk-off victory over Detroit at Fenway Park Friday night. And right in the middle of the huge win that propelled the Sox into their first playoff berth since 2021 was former Kansas City Royals reliever Aroldis Chapman, who pitched a scoreless, two-strikeout ninth inning to preserve the tie that gave his club a chance to win it all in the home half of the frame.

That Chapman held the Tigers down in such a key moment isn't at all surprising. Showing no signs of slowing down in his age-37 and 16th big league season, the fireballing lefty is one of the biggest reasons the Sox will finish the regular campaign with their first winning record since the 2021 team won 92 times but lost the American League Championship Series to Houston.

And just how good Chapman's been after joining Boston on a single-season free agent deal in December explains why the Red Sox relied so heavily on him Friday night — and why they extended that deal late last month.

Former Royals reliever Aroldis Chapman has been spectacular for the Red Sox

Proof of Chapman's incredible value to Boston is in the numbers he's posted. Through Saturday's action, his 67-game 1.17 ERA was the lowest among regular major league relievers, his 85 strikeouts in 61.1 innings were good for a 37.3 K%, his WHIP was a miserly 0.70, and his BB/9 was a decent 2.2. His 32 saves were well behind Royals closer Carlos Estévez's major league-leading 41, but his total for Boston is still outstanding.

He's been especially excellent down the stretch. Chapman wasn't charged with a single run, didn't give up any hits, and saved eight games in 12 August appearances; in September, he has a 2.16 ERA and five saves in nine games. His two-month ERA is 0.93.

And he's still dealing fire — per Baseball Savant, he's averaging 98.4 mph on his four-seam fastball and 99.4 on his sinker.

Clearly, Chapman hasn't lost anything since pitching so well out of the Royals' bullpen in 2023. Working primarily as a set-up man for Scott Barlow, he went 4-2 with a 2.45 ERA and a pair of saves, and struck out 53 in 29.1 innings before the club sent him to Texas in a late-June, pre-trade deadline period trade.

And despite the fine work he gave Kansas City, it's that deal for which he'll probably be most remembered by KC fans — it's the trade that made Cole Ragans a Royal.