Nine years to the day since he made his Major League debut, Bryce Harper might be more locked than he’s ever been at the plate.

Over his first 93 plate appearances, the Phillies outfielder has hit .329/.452/.632 with six homers and a 200 OPS+ -- three points better than his career-best mark from his 2015 National League MVP Award-winning season.

His expected stats, which are based on quality of contact rather than actual results, are even more impressive.

Harper, who played his first game for the Nationals on April 28, 2012, leads the Majors in expected batting average (.383), expected slugging percentage (.855) and expected weighted on base average (.541). His xwOBA lead is nearly 40 points entering Wednesday.

Highest xwOBA, 2021
Min. 50 plate appearances
Bryce Harper: .541
Ronald Acuña Jr.: .503
Mike Trout: .495
Rafael Devers: .495
Juan Soto: .494
xwOBA: Based on quality of contact, strikeouts and walks

But Harper isn’t merely outperforming everyone else in this key metric. He’s putting together the best stretch he’s had since Statcast started tracking in 2015.

This graph shows Harper’s rolling xwOBA average per 100 plate appearances. Each point on the graph represents Harper’s average xwOBA in the 100 PAs up to and including that point.

Prior to 2021, the highest rolling xwOBA average per 100 plate appearances that Harper ever had was .527 on June 4, 2015. He topped that on April 7 this season, with his rolling xwOBA average reaching .536. The following week, it climbed to .555 -- his new high-water mark. Again, that means his average xwOBA over his previous 100 plate appearances was .555.

Harper's rolling xwOBA average per 100 plate appearances has been over .500 every day this season, the longest run of his career.

Is the 28-year-old really better than ever? Let's take a closer look at what he's doing this season.

He’s become even more disciplined

As evidenced by his lifetime 15.1% walk rate, Harper long has been one of the most disciplined hitters in the game.

He’s managed to take it up a notch in 2021, posting the lowest chase rate of his career at 22.6% -- down from 28.0% in ’20.

Harper’s improved plate discipline has been especially impactful against non-fastballs. Taking fewer swings on tough pitches outside the zone, Harper has hit .314 with three homers and a .629 slugging percentage against breaking and offspeed pitches in 2021. He struggled on such pitches last year, hitting .226 with two home runs and a .355 slugging percentage.

Harper is still walking a ton, too, drawing 16 free passes so far (17.2% walk rate).

Meanwhile, there’s been a sharp spike in the percentage of hittable pitches he has seen overall. A year ago, just 39.1% of the pitches Harper saw were in the zone, the second-lowest single-season in-zone rate in Statcast history.

His in-zone rate is up to 45.5% this year -- a personal high for the lefty slugger, who is doing his best to capitalize on the increased opportunities.

Hard hits, sweet spots

Unsurprisingly, Harper’s penchant for crushing the ball is one of the reasons why he’s been so successful. His hard-hit rate (percent of batted balls with 95+ mph exit velocity) is 51.7%, which ranks in the 85th percentile among MLB hitters.

Hitting the ball hard is only part of the recipe, though. Harper’s hard-hit rate was almost as high last season (50.7%), but he wasn't nearly this good. The difference? He's doing more to maximize the value of his hard contact this year.

More than 30% of Harper’s batted balls have been hit hard and struck in the sweet-spot zone (launch angle between 8-32 degrees) in 2021, up from 18.7% of his batted balls last season and 20.8% across 2015-20.

Taking it a step further, Harper has increased his barrel rate -- the percentage of batted balls with the optimal combination of exit velocity and launch angle -- to 22.4%, adding almost five points to his outstanding 17.8% mark from 2020.

And Harper actually has been fairly unlucky, with an MLB-lead-tying six of his 13 barrels going for outs despite carrying a collective xBA of .822.

The caveat

As MLB.com’s Mike Petriello noted when he wrote about Harper last August, the slugger has an epic hot streak nearly every year.

Harper also happens to be one of the best first-month hitters in history, recording a lifetime 1.030 OPS in March/April. That’s more than 100 points better than his best mark in any other month (.903 in both August and September/October).

It's possible this is just another one of those big hot streaks and 2021 will end up being another typical Harper season. Which, to be fair, would still make him extremely valuable.

But there's also a chance this is the start of something bigger, like the 2015 MVP encore we've never really gotten.

After taking a step back in 2016 (114 OPS+), Harper was making a strong challenge for his second MVP Award in '17, but he hyperextended his left knee when he slipped on a wet base that August. He ended up missing 42 games and finished 12th in the voting.

It was the last time Harper received any MVP votes, but he seems poised to change that in 2021.