Tuivailala’s curveball thrived in 2019. Its career-low in wOBA (.175) and high in Whiff% (33.3%) may be due in large part to the near-perfect spin-axis mirroring (180 degrees) of his curve and sinker. Their axes’ differ by 171 degrees making either nearly indistinguishable to opposing hitters.
Tuivailala struggled with the command of his fastball in 2019. His heat map is incredibly spotty: pitches were either grooved right down the middle or thrown out of the strike zone. If he could locate more as he did here, he would have a strong chance of improving upon his fastball’s 94.3 mph exit velocity and 21.7% walk rate.
Recovery from a ruptured Achilles kept Tuivailala’s slider from reaching its true form when he first returned in July. The pitch averaged 85.9 mph that month after sitting between 87 and 88 for his career. By September he was back throwing it at 87.6 mph and struck out 40% of opposing batters.
Tuivailala leaned heavily on the two-seam fastball compared to 2017, with mixed results. The .375 batting average against is largely due to the .400 BABIP. The poor results where not due to the improved chase rate, SwStr%, and decreased zone contact against the pitch. With a high zone%, the two-seam should see better results in 2019.
The hard slider comes in around 89 mph and was thrown for strikes over 56% of the time. The slider for Tuivailala does not get many swings and misses compared to other sliders, but the .238 average against and 58% ground-ball rate shows the weak contact it induces.
Tuivailala has easy velocity on his four-seam, but has lost a tick or two over the last few years, leading him to move to the two-seamer. However, increased arm-side run has resulted in an increase in chase rate and SwStr% up to 12.7% in 2018. The BABIP was a bit fortunate but given the increased swing and miss, Tuivailala should continue to utilize the four-seam as his secondary fastball.
The curveball is Tuivailala’s secondary breaking pitch. With more neutral luck in terms of BABIP, he generated better results with an 82 wRC+. However, hitters laid off the pitch more often, as a result the SwStr% dropped 4% to 10.2% in 2018. The decrease in deception is likely due to the release point of the pitch which varies the most out of all four pitches in his repertoire.