One Big Question: Why is Jackie Bradley Jr. striking out so much again?

Welcome to Over the Monster’s One Big Question series. For those unfamiliar, this is something of a season roster preview where over the next 40(ish) (week)days we’ll be taking a look at each player on the 40-man roster prior to the season. If changes are made to the roster between now and Opening Day, we’ll cover the newly added players. Rather than previewing what to expect in a general sense, the goal of this series is to find one singular question — sometimes specific, other times more general — for each player heading into the coming season. We’ll go alphabetically one by one straight down the roster, and you can catch up with the series here. Today, we cover Jackie Bradley Jr.

The Question: Why is Jackie Bradley Jr. suddenly struggling against fastballs?

I just want to start off really quickly by verging slightly off-topic. Jackie Bradley Jr. is infamous in Boston for being so inconsistent offensively. I am not going to sit here and argue against that. I will take the opposite point of view from time to time for sake of conversation, but I’m not crazy. Anyone who watches the Red Sox on a regular basis knows that Bradley is inconsistent, at least in one specific way. From week-to-week and month-to-month, you never know what you’re going to get. That said, do we realize how remarkably consistent he has been from year-to-year? Over the last three seasons, Bradley’s wRC+ has been 89, 90 and 90. Huh! Anyway, I have nothing to add to that, but I wanted to mention it.

Anyway, on to the matter hand. Strikeouts, in a way, have always sort of been behind wherever Bradley has happened to be on his career mark. Back in his prospect days, he mostly got people excited — putting aside the defense, at least — thanks to his hit tool. The power was a question, but he was going to be get on base thanks to a good hit tool and strong plate discipline. Then, he first got called up and couldn’t make any contact whatsoever. When he finally broke out in the second half of 2015, it was largely because he cut his strikeout rate down to the low 20 percents. But since then he’s fallen back off, and over the last couple of seasons his strikeout rate has crawled back up towards 30 percent. In 2019, he finished the season with a 27.3 percent rate, the 11th-highest rate in baseball.

Now, it needs to be mentioned that part of this is simply that strikeouts are up all across the league and every year the league-wide rate gets higher and higher. In 2015 the league-average rate was just over 20 percent. Last year it was up to 23 percent. That’s a big jump in the context of league-averages. With that out of the way, however, Bradley’s issues have outpaced the trends across baseball. I’m not sure you can just point to the league as a whole to wash away all of his issues.

So, looking at his specific numbers, it shouldn’t be a surprise that he swung and missed a whole lot more in the years he has been striking out more. Turns out not making contact means you strike out more. Hand me my SABR award, please. Last season, according to Baseball Savant’s numbers, Bradley’s whiff rate was up to nearly 33 percent, a career-high and a two percentage point increase from 2018.

When you think back to Bradley’s early-career strikeout issues, it was the breaking balls that gave him issues. I know I still have images of young Bradley flailing at breaking balls down in the zone. Given that knowledge, it’s fair to expect that to be an issue here as well. It was an issue for his overall numbers, as he swung at a ton of balls down below the zone.

This certainly hurt Bradley, but he made a decent amount of contact on these pitches. The issue here was that he turned most of these low offerings over into ground balls. He saw his ground ball rate jump almost all the way up to 50 percent after a 43 percent rate in 2018 (per FanGraphs). However, according to Baseball Savant’s metrics, his whiff rates actually fell compared to 2018 on both breaking balls and offspeed pitches.

That only leaves fastballs, and this was really where the issue was for Bradley. Consider, first, that the two months in which Bradley saw the highest rate of fastballs were April and July. He finished those months with wRC+’s of 6 and 59. They also happened to be the only two months in which he finished with a below-average mark. Also consider that, while his whiff rates declined against breaking balls and offspeed pitches, his rate against fastballs jumped from 24 percent to 27 percent last year.

The issue was pitches up in the zone. Below, you will see his 2018 whiff chart compared to his 2019 chart, and you will see the numbers get worse as you move up the zone, particularly on the outer half of the plate.

As we’ve mentioned in this space before, these pitches aren’t explicitly quantified by pitch type, but we know pitches up in the zone are most often fastballs. If a pitcher is throwing a breaking ball or offspeed pitch up in the zone, it is most often a mistake.

So, what do we make of this? Well, I have no idea! I have some guesses, but it’s impossible to say anything with any sort of certainty. Bradley saw fewer fastballs in 2019, and perhaps he was sitting more on the slower pitches, which left him vulnerable to velocity. Perhaps he lost some bat speed. Perhaps he simply had trouble recognizing pitches. Perhaps it was just some bad luck. Perhaps it was a mixture of everything along with stuff I haven’t mentioned! This is a big key for him to get back to being an average hitter, though. I think we’re past the point of expecting All-Star-quality hitting from the center fielder, but a league-average bat with his defense is a really valuable player, and cutting his strikeouts is the path to get there. Of course, we don’t even know if Bradley will be in Boston in 2020, so questions are abound for the outfielder with spring right around the corner.