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Lucas Giolito has found his fastball

The former top pitching prospect is off to a solid start thanks to mechanical adjustments and a change in approach.

Boston Red Sox v Chicago White Sox Photo by David Banks/Getty Images

The Chicago White Sox have endured myriad blows to their rotation in the past calendar year. Near the end of last season, Michael Kopech had to undergo Tommy John surgery, and recently, Carlos Rodón met the same fate. There might be some semblance of hope though. Lucas Giolito, the former top pitching prospect who has been among the worst starters in all of baseball, appears to have turned a corner.

Coming into the year, Giolito owned a career 5.47 ERA and a 5.68 FIP. In 2018, his first qualified season, Giolito posted the MLB worst strikeout minus walk rate of 4.5, and no one else was especially close. The next worst pitcher in this category was Giolito’s teammate James Shields who had a 9.0 strikeout minus walk rate.

Giolito’s 2018 performance was so uninspiring that his 90th percentile projection from PECOTA projected him to be a smidge below average. After seven starts though, Giolito has pitched well above expectations.

Giolito vs. His Best-Case PECOTA Projections

Lucas Giolito K/9 BB/9 HR/9 ERA DRA
Lucas Giolito K/9 BB/9 HR/9 ERA DRA
90th Percentile Projection 7.8 3.8 1.08 3.79 4.19
2019 Actual 10.9 3.8 0.7 3.55 4.00

He’s only thrown 38 innings, so his rate starts will fluctuate. He’s probably not going to finish the year with an 8.3 HR/FB percentage, but that he’s outperforming his best-case scenario is remarkable even in a small sample.

The major difference is in the strikeout rate. Giolito has struck out 46 batters in 38 innings which translates to a 29.5 percent strikeout rate. It’s hard to fake those kinds of results. Giolito’s slider has been a major weapon for him this year, and that’s clear driver of Giolito’s sudden ability to miss bats. The slider has a 23.6 swinging strike percentage, but it’s primarily a put-away pitch. He first needs to get ahead of the hitter, and to do that, he’s needed to work on his fastball.

The most obvious change is his fastball velocity. On the year, Giolito’s has averaged 94 mph, a full mile per hour faster than where it sat his last two seasons. He began gradually adding velocity around the mid-point of last season, and now it appears to have stuck.


Adding velocity always helps, but this isn’t the only thing that’s different about Giolito’s fastball. He’s also added extra spin. In 2018, Giolito’s fastball averaged 2,099 RPM which was in the 14th percentile in baseball. Lower spin fastballs tend to sink more, and with the uppercut swing being in vogue, hitters crush the sinking fastball.

In 2019, Giolito’s average fastball spin has risen to 2,255 which puts him in the more palatable 49th percentile. The result is that Giolito has had an easier time keeping the fastball above the hitter’s bat as evidenced by the pitch’s vertical movement.

Brooks Baseball

He’s not lighting the world on fire with his fastball, but the pitch isn’t a major liability for him anymore. This confidence in the fastball has allowed him to abandon the sinker. It’s clear Giolito’s plan is to get the fastball up in the zone and the sinker doesn’t help in that regard.

Baseball Savant

Because he can keep the pitch up, he’s getting many more swings and misses with it. The fastball last year had a swinging strike rate of just 4.7, but this year it’s up to 7.5.

It’s not just that he’s getting more swinging strikes with the pitch, he’s throwing more strikes with it in general. Overall, his zone percentage is up to 49.5 from 43.7 last year. With the fastball, his zone percentage is up to 57.4 from 51.2.

Jeff Sullivan wrote about Giolito’s cleaner mechanics last August. At the beginning of the year, Giolito had a violent motion that would throw him off balance. Midseason, he raised his release point and simplified his delivery. This year, he’s gone even further with the simplification and he’s thriving much more on his short arm action.

Here’s a still of Giolito reaching back on a high fastball last September. You can also watch the pitch yourself here.

Here’s Giolito reaching back on a fastball at the beginning of May. Watch it here.

It’s hard to say definitively what the effect of his shortened motion is—his vertical release point is more or less consistent with where he ended last season—but he’s certainly hiding the ball better, and the simplified mechanics are likely leading to improved command.

Giolito may never be the perennial Cy Young candidate he was supposed to be as a prospect, but he’s looking like a competent big leaguer now. He also still very young. Giolito is just 24 and only four months older than Giants prospect Shaun Anderson who will make his big league debut on Wednesday. He’s had to make mistakes and refine his game at the highest level. That couldn’t have been easy. Giolito has had a tumultuous start to his career, but he’s ready to begin again.

Kenny Kelly is a writer for Beyond the Box Score and McCovey Chronicles. You can follow him on Twitter @KennyKellyWords.