Toolshed: Dipping into 2018 BABIPs

Context is key.
Statistics, even a simple one like batting average, can tell one story, but they don't tell the whole story. It's why slash lines (batting average/on-base percentage/slugging percentage) have come into vogue. It's one thing to note that Ted Williams hit .406 in 1941. But we have an even more well-rounded picture when we also know he posted a .553 OBP and .735 slugging percentage that season. (Both also led the Majors, in case there was any doubt.) The more data we have, the more we understand the performance.

Now that the offseason is nearly upon us, Toolshed turns to some of the game's more advanced statistics to better comprehend and evaluate how prospects produced in the Minor Leagues during the 2018 regular season.
That series begins here with BABIP, or batting average on balls in play. The stat measures exactly what it sounds like it measures -- the percentage of balls put into the field of play that fall for hits. The formula is BABIP = (H-HR) / (AB-K-HR+SF). Home runs are taken away from the numerator because they aren't "in play," while the same is done for homers and strikeouts in the denominator. Sacrifice flies, which don't count as at-bats, are added in.
BABIP can be used a number of ways, depending on the context. For pitchers, it's typically viewed as a luck stat because they don't have much say in what happens to a ball after it's hit. A great dive in center field could take away a hit just as easily as a good gust of wind could add one to the board. However, it should be noted that some pitchers are able to control that luck factor by doing a better job of producing weak contact, leading to lower BABIPs. For batters, hard-hit balls are more likely to fall in, while speedy runners are more likely to add to their hit tally by beating out throws. Luck can still play a role, and indeed it does for incredibly inflated or deflated BABIPs, but it shouldn't be the first thought that jumps to mind given the other, more controllable factors involved.
Below are some of the most extreme Minor League BABIPs produced by MLB.com's top-100 prospects this season, along with some context to better understand them. (Note, the average BABIP is typically around .300. In fact, the average Major League BABIP hasn't been above .303 or below .293 in any season since the turn of the millennium. However, the Minor League-wide BABIP -- from Triple-A circuits to the Dominican Summer League -- was .313 this season, the bump coming from quality of defenses as well as playing environments.)

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

Riley's offensive calling card has always been his power, and that certainly came into play here with the Braves third baseman producing 52 extra-base hits in 108 games, mostly at Double-A Mississippi and Triple-A Gwinnett. This is becoming a long-term trend for the right-handed slugger as well; he's only posted a BABIP below .300 with one affiliate: Class A Advanced Florida (.289) over 81 games last season. However, don't expect these types of extremes (and near-.300 average) to continue. Riley struck out in 28.4 percent of his plate appearances between Double-A and Triple-A this season but still managed a .295 average between those spots. (He also rehabbed in the Gulf Coast League.) His .415 BABIP at Mississippi alone was his highest mark in the category since 2015 with Rookie-level Danville, and it isn't sustainable going forward. Riley will get enough power behind his hits to show an average hit tool in the Majors beginning in 2019, but he just hasn't shown the ability to make enough overall contact to flirt with .300 on the game's biggest stage.
Kirilloff's season and profile are tailormade to appear here. It's easy to see that the Twins' No. 2 prospect packed a lot of punch when he made contact. His 71 extra-base hits led the Minors this season, while 51 of those were triples or doubles. The 6-foot-2 left-handed hitter's pop was mostly in the gaps between outfielders, though 20 homers are impressive as well. This is more than just luck. Obviously, few expect Kirilloff to hit .348 as he climbs the ladder, but with his power and solid 15.3 percent K rate, his high BABIPs are much more likely to follow him beyond 2018 than some others here.
Chavis fits a similar profile to Riley here, albeit in a smaller sample after he missed 80 games with a PED suspension. The top Red Sox prospect struck out in 26.8 percent of his plate appearances across three levels (mostly at Double-A Portland and Triple-A Pawtucket) but still managed a solid average, thanks to an inflated BABIP aided by his loud contact (23 extra-base hits, .538 slugging in 46 games).
Florial is a plus-plus runner who actually featured at the No. 2 spot for BABIP among top-100 prospects in 2017, when he had a .426 mark. This season's number wasn't nearly as extreme, but it's worth noting that it's inflated by his rehab time in the GCL, where he had an astounding .609 BABIP in nine games after coming back from a hamate injury. As a player who hit the ball on the ground 49.2 percent of the time and struck out in 25.7 percent of his plate appearances with Class A Advanced Tampa, Florial needed every bit of his speed to finish with a .255 average over 75 games in the Florida State League. Making more contact -- and thus taking more advantage of his speed -- will again be a point of emphasis for New York's No. 2 prospect in 2019.
Guerrero's inclusion here should come as no surprise. A player doesn't flirt with .400 for much of the season without a lot of his batted balls in play finding the right spots. That said, what's astounding is that Guerrero's BABIP is actually lower than his season average. Among the 55 position players ranked among MLB.com's top 100 prospects, only three had lower BABIPs than averages. (Keibert Ruiz and Wander Franco were the others.) Is there anything to be read into this? Well, it does underline just how extreme Guerrero's hit tool was in 2018. That, along with plus-plus power and an impressive contact rate, are what make him the most exciting hitter in Minor League Baseball right now.

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

There may have been some Rays fans who heard their club was picking up a top-100 pitching prospect/2017 first-rounder from the Pirates as the player to be named later in the Chris Archer trade, saw Baz's numbers with Rookie-level Bristol and were unenthused. For them, BABIP should be a bit of savior. The 19-year-old right-hander may have posted a 1.62 WHIP between his time with Bristol and Princeton in the Appalachian League -- 20th-best among the 23 pitchers with at least 50 innings pitched in the circuit -- but some of that may have not have been his fault. Rookie-level defenders aren't always the best, and their inability to snag balls in play may have helped his BABIP balloon to .356, the highest mark here. On a positive note, Baz did a good job of limiting contact with a 24.2 percent strikeout rate that ranked sixth in the Appy League, thanks to his plus fastball, slider and cutter as well as an above-average curve. The biggest knock against him is his 11.9 percent walk rate at this point, but it'll take a larger sample and a higher level to pin this high BABIP exclusively on him.
From the same Draft, Gore and Greene's seasons might be better remembered for their injuries than for what they did on the field. Gore was limited to only 16 starts after making three different DL trips with blister and fingernail issues. Greene's season finished Aug. 3 when it was revealed that he had sprained the ulnar collateral ligament in his right elbow. That said, the traditional numbers for both didn't make the season that much more palatable. For starters, it was the first full season for each, and as both have shown (especially Greene with his elite triple-digit velocity in the Futures Game), the stuff is reason enough to be excited. Secondly, a high BABIP did neither any favors. Greene (30.3 percent K rate) and Gore (28.4) still got their share of whiffs, and Gore even showed solid control (6.9 percent walk rate). They each had two of the 20 highest BABIPs in the Midwest League among pitchers with 50 innings in that circuit this season, and it doesn't take much imagination to wonder how much their respective ERAs would have fallen had a couple of the hits found gloves instead of holes.
Loaisiga and Dunn were two New York pitchers enjoying breakout seasons that get even rosier when you bake BABIP into the equation. Loaisiga filled the zone at both Class A Advanced Tampa and Double-A Trenton, striking out 29.3 percent of the batters he faced and walking only 3.5 percent. But opposing hitters still managed a .263 average against him, thanks in a big way to his .354 BABIP. Not that he ever had reason to worry. The Yankees gave him his Major League debut on June 15, and only a shoulder injury kept him from staying on the New York staff longer. Dunn's overall numbers were fine, and his K rate jump from 17.3 percent in 2017 to 27.1 percent between Class A Advanced St. Lucie and Double-A Binghamton this season was certainly encouraging, as he grows into a starting role. But it's not hard to imagine how much more fun his season could have been statistically had his BABIP been closer to the norm.