If you’ve been playing fantasy baseball for a few years, you know just how painful it has been to own Jackie Bradley Jr. Well, it wasn’t so painful in 2016 — his breakout year — because he slashed .267/.349/.486 with 26 home runs and nine steals.

He’s shown good speed and very good power, and given that he’s a great defender, he’s got a spot in the Boston Red Sox outfield. And because he’s in the Red Sox lineup, the runs and RBI potential is awesome.

But sadly, JBJ hasn’t followed up on that, posting a mediocre .245/.323/.402 slash line with 17 home runs and eight steals in 2017 and an even worse .234/.314/.403 slash line with 13 home runs and 17 steals last year.

He’s been frustrating to own — prone to going on incredible hot streaks followed by godawful cold streaks. But I am here to tell you that there is reason for hope, hope that Jackie Bradley Jr. might be able to finally tap into his potential in the 2019 season.

JBJ Is Changing Things Up

That’s right. JBJ is changing his approach, working in the offseason with Craig Wallenbrock, who worked with J.D. Martinez as a hitting coach.

It’s been eye-opening, as Bradley told WEEI’s Rob Bradford.

“This is the first time I heard any of this stuff,” Bradley said. “What I’ve been taught my whole life is completely wrong. It’s scary to say that, but it’s wrong. I feel fortunate enough to make it this far doing it wrong.”

In fact, Bradley started working with Wallenbrock around the All-Star break this past year. According to Bradley, Martinez told him that Wallenbrock “basically helped [Martinez] transform from the player that [he] was to helping [him] become the player that [he is] today.”

So what did Wallenbrock tell Bradley to start doing this past season? Get the ball off the ground and in the air — and hit it hard.

“Knowing I can hit the ball just as hard as [Martinez and Mookie Betts] physically, it all comes down to the way I impact the baseball,” Bradley said. “Well, I hit too many ground balls, so let’s solve that problem. Let’s get the ball off the ground, get it more in the air, on a line and that way the shifts will be beaten.”

Those Changes Look Like They’re Working

It looks like Bradley started doing exactly what Wallenbrock told him to this past year. His first- and second-half numbers are like night and day. In the first half, Bradley slashed .210/.297/.345. In the second half, he slashed .269/.340/.487.

When you dive into his batted-ball numbers, you can see that something changed in a big way this past year. He started hitting the ball a lot harder, with a 10.3% barrel rate (a career-best) and a hard-hit rate (percentage of balls hit at least 95 mph) of 49.6%, easily the best of his career, coming in at 13th-best in MLB this past season, ahead of guys such as Joey Gallo, Manny Machado, and Khris Davis.

Not only was he hitting the ball hard, he followed Wallenbrock’s advice and started hitting it better, decreasing his ground balls and increasing his line drives and fly balls.

He also evened out his launch angle much better. Below is his 2017 launch angle chart on the left, compared with his 2018 chart on the right.

That’s a lot more balls hit at a better angle last year. In fact, if you dive deeper into his batted-ball data, you can really see the changes he made.

Let’s take a look at his xStats batted ball data. In total, there are six types of hits that xStats lists:

Dribble balls (DB): These balls are the weakest-hit balls and typically don’t leave the infield. They have a very low batting average and extra-base hit rate.

Ground balls (GB): These are the next step up from dribble. They’re ground balls hit a bit more sharply than dribble balls but still rarely result in extra-base hits (though they do often result in singles — hitters had a .351 average on ground balls this past year).

Low drives (LD): These have very high success rates (hitters had a .766 average on low drives last year) but still don’t often result in extra-base hits.

High drives (HD): These are the best hits a hitter can make. They’re not overly common, but they’re great. This past year, hitters had a .656 average and, more importantly, a 2.059 slugging percentage on high drives.

Fly balls (FB): These are pretty much exactly what you think they are — fly balls hit into the outfield that don’t always result in a hit. This past year, hitters had a .253 average on fly balls. They’re not bad hits, but they’re not great either.

Pop-ups (PU): Similar to fly balls, these are exactly what you think they are — pop-up hits that are hit high in the air and almost always result in an out. So much so that hitters had a .024 average on pop-ups last year.

So let’s see how JBJ’s batted ball data has changed from 2015 through last year:

DB% GB% LD% HD% FB% PU% 2015 30.8% 17.3% 11.5% 13.5% 10.9% 16.0% 2016 27.6% 17.9% 16.9% 12.9% 7.9% 16.9% 2017 28.1% 19.4% 16.4% 10.0% 8.3% 17.8% 2018 20.5% 20.5% 17.3% 16.1% 10.3% 15.3%

The big takeaways here: The worst kind of hits, dribblers and pop-ups, hit a career-low, while the best kinds of hits, low drives and high drives, hit a career best.

It’s clear to me that Bradley started taking Wallenbrock’s advice seriously, and based on what he’s said this offseason about the work he’s been doing with Wallenbrock, he’s completely changing his approach.

When I’m looking at mediocre players who might be good in the upcoming season, I look for a definitive skill change, and I don’t think you get a more obvious skill change than what Bradley has done. If he’s able to have the success he had in half a year working with Wallenbrock, I can only imagine what could happen after a full offseason working with him.

Buried somewhere deep in JBJ is a 20/20 player — he’s got the power and he’s got the speed to do it. Maybe now with this change in approach, he could finally fulfill his potential.

And in case you were wondering, his ADP right now is 228, right at the end of drafts. The cost is low, and we’ll likely know pretty quickly if these changes are working for him or not. He’s worth a shot at the end of your drafts.

Photo by Frank Jansky/Icon Sportswire