If there’s one thing within a hitter’s batted ball profile that will send me instantly running to the hills, its a high ground ball rate. Not that putting the ball into play on the ground doesn’t sometimes have its advantages; yet, like anything in life, it’s all about moderation. Being at the extreme end of the ground ball or fly ball spectrum generally doesn’t work out for the player involved – at least not without a few sacrifices – but, at the very least, fly balls tend to lead to extra base hits. Even taking a cursory glance at last season’s leaders in each category tells a very distinct story. While players like Jon Jay, Dee Gordon and Jonathan Villar populated the top of the ground ball rate leaderboard; Rhys Hoskins, Joey Gallo and Khris Davis sported the three highest-qualified fly balls rates of 2018. There are clear archetypes developing here.

So, with that in mind, let us take a moment to celebrate those who have seemingly learned from their mistakes and have finally chosen to embrace the launch angle revolution. Let’s take a look at three players who, just last year, sat inside the top 10 in ground ball rate, but have altered their approach dramatically to almost instantaneous results.


ERIC HOSMER: 60.4% GROUND BALL RATE

There might be no player I’m more surprised to see change his ways than Hosmer, as his statistics since 2014 were essentially a one-way road with no place to turn. Hosmer’s GB/FB ratio had risen each of the past four seasons entering the current campaign, with his 3.06 mark from 2018 representing the second-highest qualified rate in all of baseball. Hosmer’s average launch angle of -1.2 degrees was also not only the lowest figure in MLB among players with more than 300 batted ball events, it was the lone sum within that grouping of 186 players to sit below zero degrees. Hosmer was truly a man in a class of his own when it came to consistently hitting grounders and the implications of this tendency were clear. The former All-Star finished his first season in California with an underwhelming .145 ISO and .309 wOBA; the latter the direct result of the LHB sporting an expected wOBA of .193 on his ground balls last season. That’s pretty damn bleak.

However, through 116 plate appearances so far in 2019, Hosmer’s batted ball profile looks almost unrecognizable. His ground ball rate of 47.4% is below 50.0% for the first time since his rookie season; his 1.61 GB/FB ratio is the second-lowest mark of his career; and his launch angle of 7.1 degrees is the highest average he’s maintained since the beginning of the Statcast era in 2015. This philosophy shift has yet to have much of an impact of Hosmer’s surface statistics – as the veteran is slashing a very similar .243/.302/.411 over his first 28 games of the season – but it only seems like a matter of time before Hosmer starts reaping the rewards of his transformation; especially if his career-best 43.0% hard contact rate isn’t a mirage. In fact, we might already be seeing the turning point of his early-season unluckiness. Going back to April 20, a span in which Hosmer owns a 1.4 GB/FB ratio, the lefty has mustered six extra-base hits in a mere 31 at-bats with an eye-popping ISO of .387. It appears the opportunity to buy-low in season-long formats might be coming to a close.


TREY MANCINI: 54.6% GROUND BALL RATE

Mancini has seen both the highs and lows of relying on a massive ground ball rate. While nothing really seemed to go in the 27-year-old’s favor last season, Mancini actually slashed .293/.338/.488 across 586 plate appearances in 2017, a campaign in which Mancini posted a 51.0% ground ball rate. It was that year that the Orioles’ slugger also benefitted from a .352 BABIP – the 12th highest mark in baseball among qualified players. Now, BABIP is mostly a luck-based stat, but it does tend to shine brightest on those who have an inclination to keep the ball on the ground. It was certainly the case that season, with Mancini managing a .327 batting average on grounders despite having an expected batting average .085 points lower within that split (.242). In fact, of the 151 players with at least 150 ground balls hit across that summer, Mancini’s xBA differentiation was the fifth-highest in the league. Then, in 2018, Mancini decided to hit ground balls at an even higher clip (54.6%); however, this time, luck was not on his side. The RHB’s expected batting average on grounders was a similar .236 by year’s end, yet his actual average on those BBEs was a microscopic .203. Without an outlier BABIP, Mancini was left a subpar average hitter with just a .174 ISO. From a fantasy perspective, he was useless.

Jump ahead to 2019 and Mancini’s a changed man. While he had already hinted at his elite contact skills by racking up 51 barreled balls in 2018 – the 16th most in baseball – Mancini’s GB/FB ratio and launch angle had served as a bit of a red flag. Consider that only four of the 42 hitters to accumulate 40-plus barrels last season did so with a launch angle below 10.0 degrees and that the lone person to do so with a launch angle lower than Mancini is the walking outlier of our time: Christian Yelich. It just didn’t seem plausible that Mancini would once again be able to manage that level of desired contact with so few of his batted ball events meeting the required launch angle standard, let alone the minimum exit velocity. However, where Mancini hit 2.06 grounders for every one fly ball last year, this season his ratio is down to an even 1-for-1. Through his first 121 plate appearances, Mancini’s hit exactly 32 ground balls and 32 fly balls, both making up 37.2% of his BBEs. That level of balance is difficult to achieve, but it’s certainly a much sought after batting profile in today’s era of baseball. This has led to the first baseman’s current slash line of .355/.405/.618; along with an expected wOBA of .381 that dwarfs his xwOBA of .332 from 2018. His BABIP will assuredly regress as the year drags on, yet, the alterations Mancini’s made to his game will help him survive the normalization.


WILLSON CONTRERAS: 52.0% GROUND BALL RATE

2018 was supposed to be the year that Contreras became an elite fantasy commodity. The much heralded catcher was coming out of a campaign that had seen him smack 21 home runs in only 377 at-bats while maintaining a .276 average and a more-than-respectable 122 wRC+ on top of that. Well, long story short, it didn’t happen; and ground balls were a huge reason why. It was really about sustainability. Contreras didn’t simply begin hitting a majority of his balls into play as grounders last season, but he had survived doing so in the past with massive HR/FB ratios masking the problem year-after-year. From 2016 to 2017, among players with at least 700 plate appearances to their name, Contreras sported the eighth-highest HR/FB ratio in baseball at a whopping 25.0%. In this time, he was also one of only three players to sport an ISO above .200 with a ground ball rate higher that 50.0%. Regression was coming and it was coming fast. So, when Contreras continued his ground ball oriented ways last season, a 9.3% HR/FB ratio derailed everything. Suddenly, Contreras’ ISO had dropped to .141 as his expected wOBA on fly balls had fallen from .789 in 2017 to a mere .354 in 2018. He’d need to switch things up going forward.

Contreras hasn’t just seen his ground ball rate come down so far in 2019, he’s almost become an extreme fly ball hitter. With a GB/FB ratio of 0.91 – easily a career-low – the backstop is now a full-fledged member of the launch angle revolution. The results of this shift in batted ball profile have been immediate, too. Contreras has smashed seven home runs in his initial 76 at-bats of the season, with his HR/FB ratio back up 31.8%. The difference now is that the RHB is hitting more than enough fly balls to maintain a 30-home run pace even when that figure starts to normalize. Contreras has also seemed to sacrifice some of his general contract skills in an effort to sell out for power; though, with a career contract rate of 72.1%, it’s not like he was the next coming of Tony Gwynn, anyway. The fact of the matter is Contreras likely had enough raw talent that he was primed for a bounce-back season in 2019 regardless of any changes in his approach at the plate; however, without hitting fewer ground balls, there’s no way he’d be close to his current .342 ISO. As along as this new profile isn’t an aberration, Contreras should continue to be an elite power hitter for his position.


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I am a promoter at DraftKings and am also an avid fan and user (my username is theglt13) and may sometimes play on my personal account in the games that I offer advice on. Although I have expressed my personal view on the games and strategies above, they do not necessarily reflect the view(s) of DraftKings and I may also deploy different players and strategies than what I recommend above. I am not an employee of DraftKings and do not have access to any non-public information.