Amid one of the best seasons of his 17-year career, Boston Red Sox closer Aroldis Chapman has reached another milestone: 400 career saves.The left-hander became the ninth reliever in major league history to achieve the benchmark Sunday, notching No. 400 in a 3-1 win over the Baltimore Orioles. Billy Wagner, with 422 career saves, is next on the career list.Earlier this season, Chapman became the career leader in strikeouts among relievers, surpassing Hoyt Wilhelm, who pitched 21 seasons from 1952 to 1972. Chapman has 1,396 strikeouts after Sunday’s win.In 17 seasons, Chapman has amassed a 2.49 ERA in 913 games, pitching for seven teams.“We’ve spoken a lot about him; it’s impressive, doing what he’s doing as long as he’s been doing it,” interim manager Chad Tracy said when Chapman reached save No. 399. “The work he puts in to keep himself in shape and keep himself able to post as much as he does, he’s pretty impressive.”The 38-year-old has been downright dominant in Boston since signing as a free agent ahead of the 2025 season. In 117 games, he’s posted a 1.55 ERA with a 34.6 percent strikeout rate, 8.1 percent walk rate and 65 saves.This year, he’s posted a 2.03 ERA with 33 saves, marking the 10th time he’s recorded 30 or more saves in a season, third-most in MLB history.After signing a one-year, $10.75 million deal for 2025, Chapman agreed to a one-year, $13.3 million extension for the 2026 season. His contract includes a $12.7 million vesting option for 2027, contingent on Chapman pitching 40 innings and passing a physical after the season. He surpassed 40 innings pitched in August.Chapman could have made significantly more by reentering free agency, but he said in August that he has liked his time in Boston and preferred the stability.Chapman has worked to turn around his career in recent years, shedding 30 pounds and honing his command with revamped workouts in the offseason. That extensive work has led to two of the best seasons of his career in his late 30s.