Pitchers Keep Pumping Heat, but Context Is Key by Tess Taruskin April 7, 2021 This is Tess’ first piece as a FanGraphs contributor. She grew up playing youth baseball just outside of Oakland during the Moneyball Era, which sparked an early curiosity about the intersection of inclusion and innovation in the sport. With a master’s degree in Computing and Digital Media, she has worked for several years as a sports video editor, creating thousands of highlight videos for high school athletes with college ambitions. She is excited to apply her technical background to prospect evaluation and the amateur draft, and further explore the ways video and data continue to evolve baseball at every level. She lives in Chicago with her husband, dog, and cat. Now that the regular season is upon us, spring training is starting to feel like something we all imagined. That’s true to an extent every season; the smaller stadiums and less familiar faces all dwell somewhere in the uncanny valley of what we recognize as professional baseball. But this year felt particularly dreamlike, with its ties and needless bottoms of the ninth. Despite these quirks, the Grapefruit and Cactus Leagues did provide the opportunity for several young pitching prospects to pitch their way onto major league rosters, solidify the roles they earned in 2020, or simply show fans what the future of their favorite club might look like. I combed through Baseball Savant’s pitch velocities from the games played at Statcast-friendly spring training facilities and compared them to those recorded during the 2020 major league season. I then incorporated reports from last season’s alternate sites and other outside sources in order to understand what these spring velocities might mean for these prospects moving forward. So, before we forget the rolled innings that ended with fewer than three outs and convince ourselves that spring training was some sort of shared hallucination, let’s take a look at some of the guys who threw harder this past month and see what that might tell us about the season ahead. Casey Mize entered the spring after a less than stellar debut season. In 2020, his ERA and FIP were both over 6.00, and he struggled with his command as he went 0-3 over six starts for Detroit. A brief look at his numbers coming out of camp might not reassure Tigers fans who focus their attention on his 7.23 ERA or the 11 walks he issued over 18.2 innings. But there is hope to be mined from Mize’s spring, especially in terms of the velocity he showcased. In 2020, Mize threw a total of 543 pitches, only five of which clocked in at 96 mph or faster, with his fastball averaging 93.7 mph. This spring, in his March 19 start against the Blue Jays alone, Mize topped 96 mph a whopping 37 times, more than half of his pitches thrown that day. This past offseason, Mize described taking a data-driven approach to correcting the issues that plagued his 2020 season, specifically focussing on refining the horizontal and vertical profiles of his slider and splitter, respectively, in order to allow an overall increase in the usage of his four-seamer and maximize its effectiveness up in the zone. In his first start of the regular season, this approach was evident, as he mixed his fastball, which sat comfortably in the 95-96 range, with his offspeed stuff to strike out three of the first four batters he faced. But when his command wavered and he found himself behind 3-1 against Luis Arraez with the bases loaded in the fourth, push came to shove, and shove he did. Mize threw five straight fastballs to ultimately retire Arraez on a flyout to center. If Mize can continue to maintain his composure under pressure, and his offseason efforts prove fruitful, the stark velocity increase he showed this spring and in his first start will be all the more valuable as he works to hold his spot in the Tigers’ big league rotation. While Mize spent his spring proving himself worthy of his roster spot, J.B. Bukauskas spent his trying to earn one. Even though the former first round pick, who the Diamandbacks acquired in the Zack Greinke deal, didn’t exhibit the same drastic velocity increase Mize did, he has shown he is capable of maintaining velocities in what was formerly considered the upper half of his range, sitting 94-95 throughout the spring. But much like jazz, sometimes it’s more about the fastballs you don’t throw. His four-seamer was most effective when he was able to locate it outside at the knees, and combine it with his changeup and late breaking slider, showing off his ability to miss bats. This spring, he racked up 14 strikeouts and no walks, allowing only three hits and not a single run in 7.2 innings of single-inning relief. Bukauskas is starting the season in Triple-A, but with Tyler Clippard on the 60-day IL, he may prove a valuable addition to Arizona’s bullpen early this season. Another prospect looking to secure a more consistent relief role is JoJo Romero, who posted solid numbers this spring, with a 1.04 ERA in 8.2 innings out of the bullpen. Over the past two seasons, he’s seen a steady increase in his velocity, ranging from 89-93 in 2019 and 93-95 in ’20, both with the big league squad and at the team’s alternate site. This spring, he continued that trend, resting comfortably in the 94-96 range, and touching 99 in his final spring outing on March 27. Considering that Jose Alvarado is currently the Phillies’ only left-handed reliever, Romero’s strong spring showing could very well earn him a bullpen spot as the season progresses. Mize, Bukauskas, and Romero all saw significant action this spring, appearing in several games each, most of which was captured by Statcast (Romero threw one inning that wasn’t captured, Bukauskas threw two). And while spring training samples are always small, they gave viewers enough of a look to draw some conclusions about how those numbers may translate to their regular season performance or projected role. But the expanded spring rosters also gave us the opportunity to take a look at some of prospects who are a bit further from the big leagues. And though their samples are even smaller than those of the players who featured more prominently in games, there are still plenty of takeaways to be had, though they often require a bit more legwork. Adam Kloffenstein, for example, is a 20-year-old righty with Toronto who isn’t expected to be major league ready until 2023. That didn’t stop the Blue Jays from putting him in for an inning of relief against the Yankees on March 14. He gave up one hit and recorded one strikeout, but context is important in assessing how his lone spring frame fits into our understanding of his budding pitching career. Having not made the cut for the 2020 alternate site, Kloffenstein played independent ball in the Constellation Energy League last year, allowing him to collect TrackMan and Rapsodo data during his time away from the Jays. This short appearance in the spring, if nothing else, seems to reinforce confidence in the reports from last year that he is now comfortably sitting 93-94, up from his previous 88-92 range. Context also comes into play when looking at Shane Baz’s two innings of work for the Rays. Prior to the spring, Baz had been presented in two distinct ways: as a starter who sat in the 93-96 range with a four-pitch mix and as a reliever who camped out in the 96-99 range, with a more limited repertoire. When Baz threw an inning against the Twins last month, he threw 23 fastballs, the slowest of which clocked in at 96.6 mph; it was clear which Baz was the order of the day. Baz’s ETA is still about a year away, but this spring may be a hint at what the Rays view as his future role. Spring training can be something of a mood ring, somehow appearing to be both green and purple. It can give viewers a sneak peek at the future of their favorite franchise, but allows enough room for interpretation that those viewers can draw their own conclusions from what’s put forth. In truth, just about every sentence above could have included a but that remains to be seen addendum. As the season progresses, we’ll be able to refine our predictions for these prospects’ performances and better determine what our takeaways should’ve been from the spring. But for now, the brief glimpse provided by the preseason gives us a good idea of what to keep an eye on as the season unfolds.