Article: Lucas Giolito Is Falling In Love With His Fastball Again

[Finley Rogan]

Lucas Giolito has had a difficult time in Boston since signing a two-year contract worth $38.5 million last offseason. Things could not have started worse for Giolito’s Red Sox career, as he experienced an elbow injury last spring which ended up sidelining him for the whole 2024 season. 

Giolito, who is now 30, was finally activated for his Red Sox debut in late April, 13 months after his initial injury, and 16 months after signing with the team. Since then, Giolito has made eight starts, posting a 5.45 ERA. Beyond the high ERA and mediocre numbers, Giolito’s inconsistency has been a major issue for the Red Sox. He has had four great starts where he pitched a combined 24.1 total innings while allowing just two earned runs. In his four bad starts, though, Giolito pitched a combined 14.2 innings while allowing a total of 22 earned runs. That Jekyll-and-Hyde performance is paradigmatic of Giolito's career.

The good news is that he seems to be coming along in a time when the Red Sox desperately need the starting rotation to step up. In his last four starts, Giolito has allowed eight runs, with seven of them coming in his disastrous start against the Angels on June 4. He looked much better on Tuesday against the Rays, as he pitched six scoreless, allowing six total baserunners.

Giolito only throws three pitches, a fastball, slider, and changeup, and he does mix in a very occasional curveball. If he has his changeup working, he is far more effective. Well, it's safe to say the changeup is struggling, with batters posting a .568 slugging percentage against it. In his five previous seasons, batters combined to slug .375 against the pitch.

This season, the stuff on the changeup has been hovering around league average. To combat that, Giolito may be looking to throw the fastball more frequently, in turn to set up his secondary pitches more effectively. Last start, Giolito threw the fastball 58% of the time, which is significantly higher than his season average of 47% fastball usage. In 2019, when Giolito broke out with the Chicago White Sox, he was using the fastball 55% of the time. Since then, the usage has gradually dropped. If Giolito is going to use the fastball more frequently now, there may be a better payoff with the secondary pitches. Case in point: Giolito has yet to allow a hit on a slider this month, but he has used it less. 

Giolito has also had decent command through his eight starts, and it might be keeping him afloat while he continues to work on his arsenal. His Location+ sits right above league average at 102. However, it is an impressive 107 on the fastball, which may be another reason for increased usage. If he can continue to locate the fastball and become more consistent with one of the secondary pitches, Giolito may be able to find sustained effectiveness in his coming starts. He is projected to pitch in Seattle to kick off the Red Sox's upcoming West Coast road trip, and then will pitch a game in San Francisco. Both ballparks are in the top three most friendly pitching environments, which could be helpful for Giolito to get rolling.

This pitch usage situation bears monitoring, especially heading into the trade deadline. A fastball-heavy Giolito could be the best version, which could make him one of the second half's most valuable starters, either in Boston or elsewhere.

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