Toolshed: Behind the BABIPs of top prospects

Since the Minor League season ended, Toolshed has looked at advanced statistics to provide a new lens through which to view position players (Spd and ISO) and pitchers (FIP) ranked among MLB.com's top 100 prospects. This edition looks at a stat that can be used for all players -- BABIP.
Short for batting average on balls in play, BABIP excludes home runs and strikeouts, while sacrifice flies are added to the mix: BABIP = (H-HR) / (AB-K-HR+SF).

BABIP is generally seen as the luck statistic, especially for pitchers, who don't have much control over what happens to a ball once it's struck. Obviously, some hurlers do a better job forcing soft contact, but there's a reason why the best ones are those who limit any type of contact (i.e., generate a lot of strikeouts). Anything else is relying on the defense to make the play.
For hitters, BABIP can involve a bit more skill. Fast runners stand a better chance at garnering more infield hits with their speed. Sluggers who generate a lot of hard contact make it tougher for defenses to make plays. There's still some luck involved -- the odd duck snort that every hitter will take, despite weak contact -- but not as much as it happens to pitchers.
For reference, an average BABIP is generally considered .300. In fact, that was exactly the Major League average during the 2017 season, and the same was true for 2016. Since the dawn of the new millennium, the highest yearly average BABIP was .303 in 2007, the lowest at .293 in 2002. In the modern age, even as other offensive categories have varied widely, average BABIP remains fairly constant.
Now it's time to dip into the BABIPs of top-100 prospects -- specifically the highest of the bunch -- to provide context around what went into their other numbers in 2017.

highest Babips for Hitters among MLB.com's Top 100 Prospects (Min. 100 AB)

There's a reason why Hiura went ninth overall to the Brewers in June: his bat. The 21-year-old second baseman, who had elbow issues that limited him to DH duty for most of 2017, showed off that impressive stick by hitting .371/.422/.611 over 42 games in the Rookie-level Arizona and Class A Midwest Leagues during his first taste of the Minors. With 25 of his 62 hits going for extra bases, that's a good amount of hard contact.
But with a .450 BABIP, it might be right to think there was luck involved. Indeed, that figure was sixth-highest among 2,385 Minor and Mexican Leaguers with at least 180 plate appearances this season. One would expect that number to fall considerably over a larger sample and against better arms as Hiura climbs the Milwaukee ladder, but look at his history. Hiura's career BABIP over three seasons at UC Irvine was a staggering .429. During his junior campaign, when he posted a .442 average over 261 plate appearances with the Anteaters, his BABIP was .516. More than half the balls he put in play fell for hits. This is a player with a high BABIP history, and that consistency speaks well of his chances to post high numbers in the Minors -- though likely not in the .450's or even .500's of this category.

It's also interesting to see Florial pop up here. The 19-year-old outfielder enjoyed a breakout season in which he hit .298/.372/.479 with 13 homers, seven triples and 23 doubles, but it's not his overall hit tool that generally pops on his scouting reports. Instead, he's a plus runner who excels defensively and can show decent power. Yet it was perhaps that combination of speed and loud contact that kept his average at a solid .298 this season, because his 148 strikeouts and 31.1 percent K rate could've been a drain. But there are some warning labels here. Florial posted a high .389 BABIP in the Dominican Summer League in 2015 but saw that number drop to .302 over three levels in 2016. (His batting average also fell out to .227 last year.) So what the left-handed slugger has right now is two high BABIP years and an average one. If Florial continues to be a free swinger, he'll need high BABIPs to help his offensive profile.
Bichette and McMahon are less surprising here. The pair went first and second among full-season Minor Leaguers with a .362 and .355 average, respectively -- no other full-season Minor Leaguer hit higher than .350 -- so of course they were going to put up relatively high BABIPs. Worth adding here is that both were driven by hard contact and certainly not speed. (McMahon is a 40-grade runner, according to MLB.com, while Bichette is simply average at 50.) McMahon, who has not posted a BABIP lower than .338 at any level in his Minor League career, saw 63 of his 167 hits go for extra bases, while Bichette's ratio was 59 out of 162. There was certainly a little luck involved to produce such ridiculously high averages and BABIPs, but it's obvious why so many people are big believers in the bats of both.
Of course, Acuna was tailor-made for a high BABIP. He's got plus speed. He's got above-average power. He made impressive hard contact to all fields. Seeing the MiLB.com staff pick for Breakout Prospect of the Year near the top of any leaderboard comes as no surprise at this point.

highest Babips for pitchers among MLB.com's Top 100 Prospects (Min. 50 IP)

Toolshed's analysis of FIP, or Fielding Independent Pitching, touched on how pitchers' statistics can be affected by factors outside their control. Not coincidentally, the main subject of that story was Puk, who is second on this table. The focus in this case will be Whitley.
Even the standard stats show that the No. 2 Astros prospect enjoyed an impressive 2017 season. After being drafted 17th overall in 2016, Whitley climbed three levels in his first full season to finish at Double-A Corpus Christi at the age of 19. He posted a 2.83 ERA, 1.21 WHIP and .230 average-against over 92 1/3 innings, striking out 143 batters. His 37.6 percent K rate was second-highest among Minor Leaguers with at least 90 innings. In short, the 6-foot-7 hurler should be one of the Minors' most promising right-handers entering the 2018 season.

But what BABIP shows is that Whitley's standard numbers -- ERA, WHIP, average-against -- could have been even stronger had he played in front of better defenses or had better luck. Consider that no pitcher in the Majors this season had a BABIP-against higher than .366 in 90 or more innings. It's bound to come down as he plays in front of more experienced defenders, and indeed, he's already gotten a taste of that. His BABIP-against at Corpus Christi was .292, albeit in the small sample of 14 2/3 innings. Had he experienced something similar at Class A Quad Cities or Class A Advanced Buies Creek, there's a chance he'd be up there alongside Jon Duplantier and Corbin Burnes as those who enjoyed truly special statistical seasons on the mound in 2017. But with the knowledge that his BABIP will likely regress going forward, the Astros have another reason to be really high on their 2016 first-rounder.
Honeywell, MLB.com's No. 3 overall pitching prospect, is in a similar camp to Whitley. He got plenty of swings and misses with 172 strikeouts in 136 2/3 innings and showed impressive control with only 35 walks between his time at Double-A Montgomery and Triple-A Durham. But his 3.49 ERA, 1.24 WHIP and .255 average-against were a little more mundane, given his stuff and command, and BABIP gives us a reason why. Honeywell's highest BABIP entering 2017 was the .299 he posted over 65 innings at Class A Bowling Green in 2015. His .365 BABIP at Durham was such an odd jump out that it's bound to regress next season, which will likely include time in the Majors at some point.
Quantrill and Anderson enjoyed successful -- albeit bumpy at times -- first full seasons after each going in the first round in 2016. Quantrill posted high BABIPs at both Class A Advanced Lake Elsinore (.353) and Double-A San Antonio (.343), and after owning a .373 BABIP-against over 37 innings in his first season in 2016, it's worth monitoring whether he'll be a high-BABIP pitcher going forward. Anderson made it past five innings in only four of his 20 starts this season. An organizational innings and pitch limit certainly held him back, but a .348 BABIP didn't help matters. The biggest correctable change he can make is to work on his control (a 12.1 percent walk rate), so that the free passes can come down as the batting average likely regresses in 2018 and beyond.