In his 2019 Big Board update, Fangraphs' prospect expert Eric Longenhagen only awarded one player a future value of 65+ in both his future hit and future game power tools. In his description of this hitter, he said "This is the best hitter in the minors and the stick will play anywhere."
With strong baseball lineage accompanying his immense talent, it seemed only a matter of time until Vladimir Guerrero Jr. lit the baseball world on fire.
Guerrero made his debut in early 2019, and despite the lofty expectations, he initially didn't live up to his top prospect billing. A 107 wRC+ through 183 career contests for a 21-year-old isn't terrible, but it surely wasn't the kind of production that earned Guerrero top prospect status.
At the heart of Vlad's struggles lay his suboptimal batted-ball profile. For Major-League hitters to succeed, their BBEs need to have two qualities: a high exit velocity and an optimal launch angle. In his first two MLB seasons, his exit velocities were top-of-the-class, but his swing prevented him from getting the necessary loft on his batted balls, leading to many harmless ground-balls.
This season, Vlad's found another gear. He lost 42 pounds over the offseason and revamped his diet to cut out any alcohol, sugar, or fried food.
His exit velocities are still top-of-the-class. He's still hitting the ball hard, as evident by his max exit velocity of 116.3 mph. His awesome raw power could be attributed to his flat bat path, which was recently explored by Fangraphs' Carmen Ciardiello.
Vlad's produced 15 BBEs with an exit velocity over 110 mph season; that mark is only topped by one other player: the otherworldly Giancarlo Stanton. His HardHit%, Average Exit Velocity, xwOBA, and Max Exit Velocity all comfortably sit in the top 10% of all Major-Leaguers in 2021.
But the difference in his production sits in his launch angle deviation.
During the last few seasons, the metric Launch Angle Tightness (sdLA) has begun making the rounds. Coincidentally, the first piece I wrote for Baseball Cloud touched on the subject, noting as that infamous ground-ball hitter Eric Hosmer increased his sdLA, his usually tepid offensive production followed as a result.
sdLA is a fancy way of talking about the distribution of a player's launch angles. Having a tight distribution of launch angles is better; research conducted by Fangraphs' Alex Chamberlain confirms that a higher sdLA correlates to better production.
As we can see in the visual below, Vlad's 2020 distribution was all over the place. But in 2021, the young slugger has made a concentrated effort to hit as many balls as possible into the buckets that produce the most barrels.
2020:
2021:
Notice how bins in the 2021 chart are more clustered together; that's what you want to see. He's also hitting more balls into the bins that produce more barrels. By hitting more BBEs in buckets with positive launch angles, Vlad can produce more damage.
Hitting more balls in the air has another benefit: line drives and fly-balls produce more barrels. As we can see from the visualization below, his production increases when he hits the ball in the air.
It's certainly a positive sign that his line-drive and flyball rates are at an all-time high. Also at an all-time high, is his barrel rates, which bodes well for Vlad's future. Barrel rates are one of the strongest predictors of future success.
Improved batted-ball profile aside, there's been a couple of other changes that Vlad's made to round out his game.
The 22-year-old has gotten more selective at the plate, always a positive improvement from any young hitter. His chase rate currently sits in the 90th percentile; a massive improvement from last year. His O-Swing % and Swing % each dipped by four percentage points while his Z-Swing% decreased by five percentage points.
Since he's taking more pitches that are out of the zone, he's driving more pitches that he can work with. Baseball Savant's Swing/Take metric visualizes this improvement.
2020:
2021:
Currently, he's leading the Majors with a +26 Run Value in the four Attack Zones. He's made significant strides in almost every zone, with only three other players posting an improvement of +22 Runs from 2020 to 2021.
In particular, he's enjoyed greater success in The Heart Zone. In the Heart Zone, which covers the strike zone, he's posted +17 Run Value, so far, a 14 Run improvement from 2020. This +14 Run Improvement from 2020 to 2021 is only topped by eight other players. Link to relevant data can be found here.
Another aspect that is aiding the former top prospect's breakout is the ability to play at T.D. Ballpark, the Blue Jays' temporary home ballpark in Dunedin, FL. As Thomas Harrigan of MLB.com noted on Twitter, Vlad's home OPS of 1.418 is first among all hitters in 2021. Jeremy Siegel of PitcherList recently explored the impact that T.D. Ballpark had on offense; he concluded that the stadium had a slight improvement on a team's offensive performance.
Overall, Vlad's triple-slash of .331/.444/.632 is anchoring a Blue Jays' lineup that has faced a litany of injuries this season. Several of their starters have missed a significant amount of time and offseason acquirees George Springer, Steven Matz, and Kirby Yates haven't panned out as expected. But with the majority of their injured players on the way back, the Blue Jays could be primed for a second-half run, with Vlad Jr. leading the charge.
After all, he was a former top prospect for a reason.