Toolshed: BABIP and top prospects

In play, out(s).
In play, no out.
In play, run(s).
These are common phrases to anyone who has followed an MLB.com or MiLB.com Gameday feed in the past two decades. It seems simple enough with three types of general outcomes once the bat meets the ball and the ball stays within the lines of play, but over the course of a long season, the differences between what lands in a fielder's glove, what lands on the green grass or the soft dirt and what lands in a fan's hand beyond the outfield fence don't just have immediate effects. They pile up over a season and can make an OK season look great or an otherwise impressive campaign look mundane.
Enter BABIP.

BABIP, or batting average on balls in play, provides context to the usual stats used to evaluate performance. It's calculated by the following formula -- BABIP = (H-HR)/(AB-K-HR+SF). In other words, what percentage of balls that don't go out for homers or end up as sacrifice flies fall in for hits?
Average BABIP is typically around .300. (Major League average BABIP in 2019 is, in fact, .299.) Anything significantly higher or lower than that leads to questions. Lots of hard contact or tons of speed from a batter can elevate BABIP while a lack of either can bring it down. Pitchers typically have less of an impact on their BABIP, but giving up a ton of hard-hit balls certainly doesn't help the stat. Then there's always luck. Hitters talk often about squaring balls up, only to hit them right at defenders. This is becoming more of a problem with the growing popularity of shifts, which sometimes replaces luck with strategy. It may be unfortunate to hit a ball right at the shortstop, but if the shortstop is playing behind second base because of the batter's proclivity to pull the ball or go up the middle, then luck isn't an issue.
Whatever the case, context is key. This week's Toolshed looks at the highest BABIPs posted by Top-100 prospects in 2019 on the hitting and pitching side and evaluates what led to those inflated statistics.

Highest BABIPs for hitters among MLB.com's Top-100 prospects (min. 300 AB)

Waters' numbers should look like an extreme outlier here, considering his BABIP was 37 points higher than his closest competition. The difference between him and second-place Lux is roughly the same as Lux and Carter Kieboom, who ranks 11th in the category at .362. But it goes even deeper than that. Waters' .435 BABIP was the highest among all 945 Minor League hitters with at least 300 at-bats.
So why did that happen? For starters, Waters doesn't put the ball in the air that much. His 27.6 percent fly-ball rate between Double-A Mississippi and Triple-A Gwinnett was 888th-highest among Minor Leaguers in this group. Balls in the air, while more likely to go for homers are also more likely to be caught by defenders. Waters was much more likely to hit the ball on the ground (46.1 percent) or on a line drive (26.2 percent). In the case of the latter, he was practically elite, ranking 33rd overall in the Minors in line-drive rate, putting him in the top 3.5 percent. Line drives, by their nature of being hard-hit balls, can make for tougher plays by fielders and lead to higher BABIPs. When Waters hit the ball on the ground, which he did most of the time, he could rely on plus speed to beat out a few more hits or force tough plays from fielders knowing he's hustling down the line. 

There's no doubt that Waters' .435 BABIP will be difficult to repeat going forward as he approaches the Majors. But through three Minor League seasons, his career BABIP sits at .403, and he's shown the batted-ball profile and skill set to continue producing such relatively high numbers in the category.
Elsewhere, it might not be a surprise to see Lux here during his special season. The top Dodgers prospect's .358 BABIP at Double-A Tulsa played nicely within his career norms, but the stat especially took off at Triple-A Oklahoma City, where it was a staggeringly high .451 through 49 games. The biggest difference between the two spots was Lux's ability to get the ball off the ground; his ground-ball rate dropped from 49.8 percent at Tulsa to 45.5 while his fly-ball rate climbed from 26.4 to 32.5. That doesn't fully explain the gigantic jump, which could be utilized as a test case for the difference between Triple-A and Double-A baseball. The new Triple-A ball (the same as the one used in the Majors) famously saw a home-run explosion at the Minors' highest level, and that may have come to BABIP as well. Across the two Triple-A leagues, BABIP went from .317 in 2018 to .324 in 2019. It's not a huge jump like the one in dingers, but it is noticeable. Also, that .324 in Triple-A was an even bigger leap from the .304 average BABIP from the three Double-A leagues. There probably was still some luck involved in Lux's killer BABIP in Oklahoma City, but the ball certainly didn't hurt.

Well-known hard hitter Rodriguez, Larnach and Adell round out the top five.
Rodriguez's numbers got an especially big lift by his .528 BABIP in 17 games at Class A Advanced Modesto, as if anyone needed another reason to believe his .462/.514/.738 line in the California League isn't reproduceable. Larnach was much more consistent -- .389 at Class A Advanced Fort Myers, .390 at Double-A Pensacola -- but this might speak more to his power potential than his 13 homers combined between the two spots. Just because he didn't send balls over the fence in pitcher-friendly environs, that doesn't mean the Twins left-handed slugger isn't capable of producing the high exit velocities that defenders can't handle. Larnach similarly posted a .379 BABIP during his three years at Oregon State. That number could drop as his home-run production increases in the years to come, but it may not mean there will be a similar drop in batting average. (Homers are still hits, remember.) Adell has posted fairly high BABIPs through his young career, and it was promising to see that continue following multiple leg injuries in the spring. When he's hitting on all cylinders, the top Angels prospect has both the plus speed and powerful bat to pick up hits on balls in play. However, his .410 BABIP against a .264 average over 27 games at Triple-A Salt Lake point out how he'll need to work on making more contact against upper-level arms. His average in the Pacific Coast League was dragged down by a 32.6 percent K rate more than anything about balls in play.

Highest BABIPs for pitchers among MLB.com's Top-100 prospects (min. 50 IP)

Fifty innings doesn't make for a significantly high threshold, but it was set at that point to include Whitley, whose numbers deserve some investigation after an obviously tough season.
The Astros' No. 2 prospect entered 2019 as the game's top pitching prospect and a hurler who many expected would impact the big club in Houston at some point in the months to follow. What followed instead was a rough first trip to Triple-A followed by a shoulder injury and a slow climb back up the ladder as a rehabber. You can see how that went above. On the positive side, there were lots of strikeouts. On the negative, lots of everything else.
On its face, BABIP would appear to tell us Whitley was fairly unlucky in that balls in play inflated his other numbers. However, more context doesn't let him get off that easy. During his time in Triple-A alone (where he posted a .400 BABIP-against), Whitley's line-drive rate was 32.4 percent (highest of his career) while his ground-ball rate was 31.1. What's more, he gave up 35 hits in 24 1/3 innings with Round Rock, and of those 35, 20 went for extra bases. His nine homers allowed don't count toward BABIP, but the picture tells enough of a story. When Whitley was hit in the Pacific Coast League, he was hit hard. The 22-year-old right-hander has time to figure things out -- he is currently working in the Arizona Fall League -- and he has the deep repertoire with four plus pitches to marry his high strikeout total with much weaker contact going forward.

Garcia is another interesting test case. The 5-foot-9 right-hander made a name for himself with high K totals in a breakout 2019, including a 15-strikeout night for Double-A Trenton on June 18. He fanned 34 percent of the batters he faced across Class A Advanced Tampa, Trenton and Triple-A Scranton/Wilkes-Barre, and though he struggled at times with control, his 11.1 percent walk rate wasn't enough to explain the rough 4.28 ERA. Instead, that number might have come down to actual bad luck. The Yankees righty's BABIP fluctuated wildly from .288 in 2018 to .352. The batted-ball data wasn't enough to contribute to that jump -- the two years were fairly similar -- and Garcia didn't give up a ton of hard contact. At Triple-A, 18.2 percent of his fly balls went for homers, although those didn't count against BABIP since they weren't in play. In fact, his .313 BABIP-against with the RailRiders was lowest among his three affiliates in 2019. It's worth monitoring going forward, but if anyone was scared off by Garcia's ERA or WHIP in 2019, BABIP should be a reminder that it wasn't fully his fault.
Similarly, Lynch didn't do anything that immediately points to a high BABIP in 2019, but ended up with one anyway. Indeed, the 22-year-old southpaw was primarily a ground-ball pitcher when healthy for Class A Advanced Wilmington, putting the ball on the ground 47.5 percent of the time, but still finished with a .324 BABIP there. That stat took another jump in rehab stints in the Rookie-level Arizona and Rookie Advanced Appalachian Leagues, but those were at times when the Royals' No. 3 prospect was trying to rediscover his form after missing time with an arm injury. It's more likely answers will be easier to find in Lynch's balls-in-play data when he enters his second full season in 2020.
As mentioned with the Triple-A ball, Keller's BABIP numbers weren't that much higher than the average for the level during his time with Indianapolis, and it's a good reminder that his 3.36 ERA would have led the International League had he not fallen a few innings shy of the qualification minimum. 
As one can expect, Dunn's .314 BABIP at Double-A Arkansas is nothing to worry about, given how close it is to what's traditionally considered average, but when placed among a group of the Minors' best pitchers, it still pops up among the highest five.