Vladimir Guerrero Jr. is off to one of the hottest starts to the young 2021 season, and it’s been a ton of fun to watch so far. Guerrero has reached base safely in all 13 of the Blue Jays’ games this season, so if you’ve watched a game, odds are you’ve seen him aboard -- and crushing the ball.

He has a 1.200 OPS, eighth-highest among qualified hitters. His .413 batting average ranks sixth. Sure, those numbers are the product of an early-season small sample -- nobody is expecting a .400 hitter this season, let alone the seven currently on the leaderboard. And he crushed the longest homer of his career on Thursday night: 456 feet.

Of course, Guerrero has had notable streaks before. If we evaluate his performance with his expected weighted on-base average (xwOBA), which goes beyond batting average or slugging by considering strikeouts, walks and quality of contact (exit velocity and launch angle), he’s had 50-plate appearance spans in the range of his current .434 in his last 50 PA, in both 2019 and 2020.

But thanks to the underlying metrics and process stats that Statcast affords us, there’s reason to believe that this time, Guerrero’s hot start is for real.

Quality of contact
From the moment he set foot in the Majors, Guerrero has been expected to mash the ball. And in instances, he has -- nobody has more batted balls with a 115+ mph exit velocity than his 14 since his debut. In his rookie year in 2019, his maximum exit velocity was 118.9 mph -- that’s Giancarlo Stanton territory -- but overall, that type of contact was not the norm. His hard-hit rate was just 38.7%, a 48th-percentile mark.

In 2020, that raw power really materialized, and he posted a 50.8% hard-hit rate, meaning that he made 95+ mph exit velocity contact more than half the time. That was 93rd-percentile and much more in the range of what we had seen, anecdotally, from Guerrero in the Minors, but still, he hit .262 and slugged .462. Part of what kept him from fully utilizing his power? Ground balls. His ground-ball rate rose in 2020, to 54.6% from 50.4% in 2019. This is why we talk about quality of contact: it’s hard to capitalize on a well-hit baseball when it is hit into the ground.

So far in 2021, Guerrero is hitting the ball in the air more, with that ground-ball rate down to 41.7%. His average launch angle is 11.6 degrees, which would be his highest in any year of his career, and lo and behold, more of his hard-hit batted balls are going for hits, and extra bases, at that. He's currently hitting .824 and slugging 1.529 in at-bats ending on a hard-hit ball this season. Those numbers have some early-season small sample to them, but they're well above his prior career averages on hard-hit batted balls.

His hard-hit rate is down a bit, at 47.2%, but with more elevation, it’s been a great combination. His expected batting average of .338 and expected slugging percentage of .580 are both far higher than his marks for those quality of contact-based metrics in 2019 or 2020. His expected stats on hard-hit batted balls are also higher than ever before, a .672 xBA and 1.304 xSLG, which tell us that he's making better contact when hitting the ball hard -- that's where the launch angle and keeping the ball off the ground helps back up that what he's doing is for real. He’s making more quality contact, and it’s paying dividends.

Plate discipline
Another key component to Guerrero’s start that foreshadows long-term success is his eye. As MLB.com’s senior data architect Tom Tango recently pointed out on Twitter, we can see these improvements with Guerrero’s 2021 swing/take numbers, which assign run values to each pitch based on outcomes and can quantify a player’s value in different parts of the zone.

Guerrero currently has 10 swing/take runs, tied for second most in the Majors behind only Ronald Acuña Jr. The biggest thing is that Guerrero is chasing less. That’s particularly notable since he’s seeing fewer pitches in the zone, so there have been even more out-of-zone chances to chase. And he's made the most of those in-zone pitches, as his eight swing/take runs in the 'heart' of the zone are the most in baseball. That indicates great plate discipline choices on those pitches. Tango compared Guerrero’s 2021 swing/take chart to that of “batting genius Juan Soto,” the best hitter in baseball.

Putting the ball in the air more is the solution for best optimization of Guerrero’s raw power, but this plate discipline component is just as important for his overall success. And as he continues to hit well, it’ll matter even more as he sees fewer and fewer pitches to hit. This zone awareness will help him capitalize on the chances he does get, and take his walks otherwise. He has a 15.8% walk rate this season after an 8.2% mark in 2020 and 8.9% in 2019. That 7.6 percentage point increase from 2020 to 2021 is the seventh-highest of any hitter who was qualified last year and has at least 50 PA this year.

He’s added some speed, too
Guerrero’s weight loss in the offseason was a storyline, and so far, we’ve already seen a speedier player on the field. He seems unlikely to ever be a basestealer with any reliable frequency, but his average sprint speed is up 1.6 ft/sec in 2021, at 26.9 ft/sec after 25.3 ft/sec in '20. That’s still just below the league-average figure of 27 ft/sec, but it’s a lot closer, and speaks to the growing picture of Guerrero as a more complete player. That sprint speed gain is among the top increases so far in 2021.

The road ahead
Of course, as noted earlier, we’ve seen hot streaks from Guerrero before, and we’ve all seen players across the board get off to unsustainable or unfounded starts to seasons. But given Guerrero’s increased quality contact and plate discipline improvements, he has the tools to keep this up throughout the year. It’s worth remembering that Guerrero is still just 22 years old, and these are already impressive adjustments he’s made at the Major League level.