While the stars of today were wrapping up the postseason, the stars of tomorrow have been showing off their skills out west in the Arizona Fall League. On Saturday, with the Major League calendar completed, many of baseball's best prospects took the stage in front of a national audience.
The Fall Stars Game has offered first glimpses of many of the game's current superstars, from Michael Trout to Kristopher Bryant to Byron Buxton, as scouting reports met with the eye-test for fans looking toward the future. But with the game at Salt River Fields in Scottsdale, Ariz., we've gained another tool at our disposal: Statcast™'s player tracking technology. While characteristics like fastball command for pitchers or plate discipline for hitters usually takes time to develop, Statcast™ shows us some of the raw tools these prospects already possess. High spin rates, scorching exit velocities and off-the-chart speed are traits that don't necessarily need large sample sizes to analyze.
:: 2017 Arizona Fall League Fall Stars Game ::
With that in mind, here are the Statcast™ plays that stood out from the East's 4-2 victory, as well as the Major League stars that those plays reminded us of.
Top 1st: Tomas Nido throws out Ronald Acuna on a caught stealing
MLB comp:Austin Hedges, Padres C
Acuna's 60-grade speed has generated about as many raves as his bat this fall, and he showed a glimpse of that when he led off the game with a single and then took off for second on a steal attempt. MLBPipeline.com's No. 5 overall prospect reached a top sprint speed of 29.4 feet per second, according to Statcast™, which brushes up against the 30 ft/sec benchmark for elite speed inhabited only by Buxton and Billy Hamilton.
• Major talent on display in Fall Stars Game
Unfortunately for Acuna, an even better throw by Nido sent him jogging back to the dugout. Nido, the Mets' No. 9 prospect, rose and fired with a pop time of 1.91 seconds and fired an accurate 82.9-mph throw to second. For context, Yadier Molina's 82.9-mph average on "max effort" throws (or those within his 90th percentile or higher) ranked 11th among full-time MLB catchers in 2017. But Nido's pop time clocked in well under the MLB average of two seconds, and would likely have been a highlight for Hedges, who topped all full-time catchers with a 1.95-second average pop time on max effort throws to second this year. Nido might not pull off such a quick transfer on all his throws moving forward, but when faced with a tough test in Acuna, he passed with flying colors.
Bot 1st: Victor Robles steals second base
MLB comp: Buxton, Twins CF
Robles, of course, was the other player who brought a reputation for game-changing speed into the Fall Stars Game. MLBPipeline's No. 2 overall prospect scored seemingly in the blink of an eye after leading off with a walk, and it was the way he did so that was as impressive as how fast he did it. Facing Pirates prospect Mitch Keller, Robles only ventured 12.3 feet into his secondary lead before darting for second base. That secondary lead was roughly eight feet shorter than the Major League average on successful steals of second over the first two years of Statcast™ data, meaning Robles gave himself an extra degree of difficulty. But Robles made it in safely with a headfirst slide after reaching a blazing top sprint speed of 30.2 feet per second.

How fast is 30.2 feet per second? That happened to be the same sprint speed average that made Buxton MLB's fastest player in 2017. It should be noted that only max effort runs of at least two bases are factored into the averages on Statcast™'s sprint speed leaderboard, but 30.2 ft/sec is still elite speed, no matter what kind of play it's recorded on. Furthermore, we already know Robles' speed translates to the Majors after he set the Nationals' fastest home-to-third time in Statcast™ history two months ago.
Top 8th: Brennan Bernardino strikes out Austin Riley
MLB comp:Seth Lugo, Mets P
Riley fouled off two consecutive curveballs in this at-bat before Bernardino froze him with another hook for strike three. Why are we focusing on this specific pitch? Because Bernardino's curve registered a spin rate that's hardly ever seen at the Major League level: 3,063 RPM. A curveball with over 3,000 RPM is a rare breed; only 2.5 percent of all curves thrown at the big league level this season rotated that much. In the first three years of Statcast™, we've seen that higher-spin curves tend to generate more groundballs and swings and misses than average. In fact, MLB hitters as a unit slugged just .247 against 3,000-plus RPM fastballs in 2017.

Unfortunately, we've yet to see a Major League pitcher find success by repeatedly throwinge 3,000-plus RPM curveballs. The best example is probably Lugo, who routinely rips off elite-spin curves but had to navigate a partial tear in the UCL of his pitching elbow in 2017. Lugo hasn't thrown his curve more than 18 percent of the time in either of his first two seasons, perhaps due in part to that injury concern. Still, the potential remains for Lugo as it does for the Reds' prospect Bernardino with that kind of stuff, and Astros teammates Lance McCullers and Charlie Morton showed how elite-spin curveballs can shut down a lineup during Houston's run to the World Series title this autumn.