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 homestand last month.

The right-hander, 30, was Boston’s most significant free-agent pitching signing last offseason. He suffered a UCL injury in his second spring training game, and underwent season-ending internal brace surgery on March 12.

It was a stunning turn of events for the Sox and Giolito, one of the game’s most durable starters over the last half-decade. Between 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 the shortened 2020). Pitching for the Chicago White Sox, Los Angeles Angels, and Cleveland Guardians in ‘23, he’d 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 board since, 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 took significant steps forward this year, including Tanner Houck, Kutter Crawford, and Brayan Bello, who became the first homegrown trio to each make 30 starts for the Red Sox since 1987.

For Bailey and Co., helping Giolito limit free passes and induce weaker contact will be key. Between the ‘19 and ‘21 seasons, his walk rate jumped from 7.2% in ‘21, to 8.7% and 9.2%. After holding opponents to a .394 slugging percentage and 34.4% hard-hit rate in ‘21, they slugged .455 and .482 against him with hard-hit rates of 39% and 41.6% in the subsequent two years. He gave up home runs at a 5.2% clip in ‘23, a sizable increase from the 3.5% he’d allowed over the previous five seasons.

By opting in, Giolito also triggers a pair of potential options for the following 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 $1.5 million buyout.