Lucas Giolito officially exercised his $19 million player option for 2025 on Thursday, making official what he previously announced during the Red Sox’s final game last month.

The 30-year-old right-hander was Boston’s top free-agent signing last offseason. He suffered a UCL injury in the second game of spring training and had season-ending internal surgery on March 12.

It was a stunning turn of events for the Sox and Giolito, one of the game’s most durable starters of the past half-decade. From 2018-23, he made 167 regular-season starts, totaling 947 innings. Before signing with the Sox, he made at least 29 starts in each of the last five seasons (not including a shortened 2020). Pitching for the Chicago White Sox, Los Angeles Angels and Cleveland Guardians in ’23, he made an American League-leading 33 starts.

Giolito broke out with the White Sox in 2019, his only All-Star year to date and the first of three consecutive seasons in which he received American League Cy Young votes. He pitched to a 3.47 ERA and 1.076 WHIP over 72 starts during that three-year span, but has struggled to keep runs off the plate since then, posting a 4.89 ERA and 1.370 WHIP over 63 starts between ’22-23.

Under new pitching coach Andrew Bailey and a revamped staff, several Red Sox starters have taken big steps forward this year, including Tanner Houck, Kutter Crawford and Brayan Bello, who became the first home run trio to each make 30 starts for Red Sox since 1987. .

For Bailey and Co., helping Giolito limit free passes and induce less contact will be key. Between the ’19 and ’21 seasons, his walk rate increased from 7.2% in ’21 to 8.7% and 9.2%. After holding opponents to a .394 slugging percentage and a 34.4% slugging percentage in ’21, they’re hitting .455 and .482 with a 39% slugging percentage and 41.6% in the next two years. He gave up 5.2% of his home runs in ’23, a considerable increase from the 3.5% he allowed over the previous five seasons.

By opting out, Giolito also triggers a pair of potential options for next season. If he pitches at least 140 innings in ’25, he’ll unlock a $19 million mutual option for ’26. Otherwise, the Red Sox hold a $14 million club option or a $1.5 million buyout.