Last winter, we ran an article titled "Jackie Bradley Jr. ... is poised to break out." We based it on his elite hard-hitting skills, on his hot finish to 2018, on all the hard work he claimed that he'd put in to revamp his swing with J.D. Martinez's hitting coach. It was going to be his year, and we weren't alone in saying it. (It wasn't the first time we'd said it, either.)

All looked great in Spring Training, when he hit three homers with a 1.024 OPS.

Then the season began. It ... didn't go well.

Bradley didn't hit a homer until the middle of May. He didn't get his average above .200 until June 13, just a week ago. As late as May 15, barely more than a month ago, we were talking about his season in terms of weakest hitting seasons ever. He's still only hitting .210/.310/.366. It's easy to point to his season to date as a disaster, and maybe it is. But to merely write off his 2019 due to that stat line is a mistake, in the same way that a reliever who has one or two terrible outings in April has to wear an ugly ERA for weeks or months until he can get it down, even if it's not representative of who he is.

Bradley has long been one of the streakiest hitters in the Majors, and this year is no different. We're already seeing signs of life. If you can look past the .210 average, you might just be able to see the hitter the Red Sox hoped they'd have.

When trying to find the point of the 2019 season where Bradley truly bottomed out, you'll find different answers from different sources. Bradley himself says he felt it "click" doing pregame work on May 25 in Houston. Red Sox manager Alex Cora thinks it was the day before Bradley's first homer of the year, off Toronto's Elvis Luciano on May 20. There's probably not "one right answer" here, but we'll follow the numbers, which happen to mirror what Cora said: Bradley's numbers reached their nadir on May 19.

That day, after an 0-for-3 against the Astros, Bradley's line sank to a miserable .144/.245/.176, the worst OPS (.421) of any qualified hitter. So we'll go with the numbers, and we'll go with Cora, splitting Bradley's season into "through May 19" and "since May 20." The differences are drastic.

Through May 19

• .144/.245/.176
• .421 OPS (worst of 171 qualified hitters)
• 11% walk rate, 30% strikeout rate
• 59% grounders (second highest of 172)
• 41% hard-hit rate

Since May 20

• .293/.391/.606
• .997 OPS (22nd-best of 188 qualified hitters)
• 10% walk rate, 24% strikeout rate
• 47% ground-ball rate (tied for 53rd-highest of 188)
• 39% hard-hit rate

Through May 19, he was the worst hitter of, well, anyone.

Since May 20, Bradley is out-hitting MVP candidates Cody Bellinger and Anthony Rendon. He's out-hitting Josh Bell and Martinez. He's been fantastic, and he's doing it with his usual outstanding defense. Streaky as he may be, this can't just be about "hot" or "cold." What's changed?

As you can see above, it's not about hitting the ball harder, because that's not really happening. It seems to be about these things ...

It's a little about contact.

Contact is good, so long as it's good contact, and Bradley is making more of that. You can see that above, as his 30% strikeout rate was one of the 15 highest among qualified players, and his 24% strikeout rate since is a mere 58th-highest. The why of that is a little more difficult to explain, but let's start with this: He's not striking out so much.

It's maybe more than a little about grounders.

"There's no slug on the ground," goes the common refrain of the last few years, and that also holds true for Bradley, who is currently holding a 53.2% grounder rate, which would, by far, be a career high. But as you can see, he's had a big before/after drop from 59% to 47%, which would put him back in line with his career norms.

It's possibly a lot about where he's hitting the ball.

Remember that home run that Cora spoke about, off Luciano? It was hit to the opposite field. That's not something Bradley was doing much of through May 19, posting a pull/center/oppo line of 44% / 35% /21%. That's changed since May 20, as it's now 33% / 39% / 28%.

Last year, when Bradley had success, it largely was to the opposite field.

• 2018 pull OPS: .659
• 2018 center OPS: 1.023
• 2018 oppo OPS: 1.194

This year, that's a gap that's even larger.

• 2019 pull OPS: .574
• 2019 center OPS: .667
• 2019 oppo OPS: 1.585

Combining 2018-19, only five hitters in the game -- good ones, too, in David Freese, Javier Baez, Aaron Judge, Juan Soto, and Tommy Pham -- had a higher opposite-field OPS than Bradley's 1.327. Only seven hitters had a worse pull-field OPS than Bradley.

If it's easier to look at it visually, well, here's a heat map of Bradley's extra-base hits since the start of 2018. The effect should be clear. Not every hitter wants to go to the opposite field. For Bradley, it's where he lives.

It may or may not be about a swing change, but there's been one

As you can see in this comparison from two games this year, April on the left and June on the right, Bradley has replaced the toe tap in his front foot with a more pure leg kick that doesn't touch the ground.

"Bradley had been struggling with the timing of the weight transfer in his swing all season, rushing forward too early with his front leg in a way that disrupted the timing of his swing," wrote Alex Speier in late May.

This isn't declarative evidence that it's a cause of his success, because we can't say for sure that it is, and he's been going back and forth with his stance for years. It does, however, appear to be a thing that's different, and that's notable when we're trying to find proof of change.

That's really the Bradley story, it seems. The only thing consistent about him is his strong defense and great arm. We're now more than six years into his Major League career, and the next season he has where he's productive for six straight months may be his first. That might limit his overall upside, but that doesn't mean that the player he was for the first six weeks of this season is the player he's going to be for the rest of it.

The scoreboard may show a .210 average or a .676 OPS when he comes to the plate, and those aren't good numbers. But as you can see, he's already different, and he's been one of the best hitters in baseball for a month now. Humbled by his slow start, Bradley discussed the frustrations of slumping with The Boston Globe a few days ago.

We know he has the talent to keep this up ... right until the next slump, that is. For so long as he does, there are few players more valuable than a power-hitting, defensively strong center fielder -- and that's a big deal for a Red Sox team that's still very much in the playoff hunt.