Rondon has never placed an emphasis on his changeup. Last year saw a career high in usage at a minuscule 4.4%, but this figure could go up as he follows suit with the rest of the league in dropping his fastball percentage.
It feels like Rondon has been around for a million years, but he can still dial it up. Sitting in the 94th percentile of fastball velocity helps Rondon to limit hard contact on his fastball (86.6 EV) while setting up his slider.
Rondon registered his lowest number of strikeouts (48) since his debut season. His slider, a go to secondary offering, has fantastic vertical break and is particularly effective against righties, however an ugly 1.48 HR/9 and a 3.1 point drop in K/9 (from 10.2 to 7.1) doesn’t bode well for the future.
Rondon attacks hitters with an overpowering fastball that consistently flirts with triple digits. Despite the pitch having a low spin rate given its high velocity, Rondon still blows it past hitters at a high clip. Rondon utilizes his heater on more than half of his pitches, which has resulted in resounding success
Rondon’s slider has been overwhelmingly used as his go-to secondary offering since 2015, and it generates whiffs at a ridiculous rate. Despite almost exclusively featuring his slider in his offspeed arsenal, the pitch gives opposing hitters fits as it darts away from righties (and in on lefties’ hands). Statcast metrics suggest that despite the effectiveness of Rondon’s slider in last season, its results were worse than the quality of contact induced on the pitch would indicate.
Rondon seldomly utilizes his two-seam fastball and rightly so. He struggles to find the zone with the pitch and allowed a near .300 BAA on the pitch in its limited usage last season.
Rondon threw 42 changeups in 2018, and it graded out as a below-average pitch. While he did not allow a home run on it, he walked twice as many batters as he struck out and rarely missed bats with it; batters made contact with his changeup 95% of the time. The one positive is the majority of the contact resulted in ground balls, as Rondon generated a 78% ground-ball rate.