What the heck happened with Jackie Bradley Jr.’s offense in 2021?

When the news first broke that the Boston Red Sox traded Hunter Renfroe to the Milwaukee Brewers for a package that included Jackie Bradley Jr. as the lone major-league piece to come back, a lot of the initial discouragement regarding the move was around the idea that Bradley would be a key component of the 2021 roster. It’s not to say there’s no reason to be against the trade, but that specific idea is misguided. After the season he had with the Brewers in 2021, there’s essentially no chance he’ll be pencilled into the starting lineup whenever camp begins. On the other hand, they didn’t trade for him for no reason, and he will presumably have some sort of role next season. So with that in mind, it’s worth diving into what exactly led to Bradley’s dreadful 2021.

It’s no exaggeration to say that the veteran was among the worst hitters in baseball, and he may in fact have been the worst hitter in the game this past season. Bradley finished his lone season outside of Boston hitting .163/.236/.261 for a 35 wRC+ (meaning he was 65 percent worse than league-average by that metric). He finished the season almost a full win below replacement level despite, by FanGraphs’ measure, playing the best defense of his career since 2015. To find a player who had a worse offensive season by wRC+ you have to set the plate appearance minimum to 185. Bradley came to the plate 428 times.

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So, after putting up that kind of season, as we said above there’s just no way an ostensibly contending team can put him among the starters. But again, he will play some role, and when digging into the numbers you find that the problems were, well, everything. Bradley has always had some mild strikeout issues, but his 31 percent rate this past season was the worst of his career. Likewise, his 6.5 percent walk rate was well below his career norms and was a career-low, and his Isolated Power (SLG - AVG) came in at .098, the second-lowest mark of his career after 2014, his first full season in the majors. To put it more succinctly, he struggled both with plate discipline and quality of contact.

To me, the strikeout issues and the more general plate discipline shortcomings are the most concerning sign here as everything sort of plays off of that. Here, the problems are pretty clear and reflective of what we learned from his time in Boston are signs of him having issues at the plate. Bradley expanded the zone too much, with his 27 percent chase rate (per Baseball Savant) coming in roughly tying his career-worst rate. To make matters worse, his 43 percent contact rate on those swings against pitches out of the zone was far and away the lowest mark of his career, and it came in a whopping 16 percentage points below league-average.

Like I said above, that should sound familiar with people thinking back to Bradley’s first stint in Boston. He was a notoriously streaky hitter and always managed to swing his way out of these ruts, but we’ve seen many times when he is going badly and whiffing time and again on pitches out of the zone. Breaking balls always seemed to be the kryptonite for Bradley, and they were certainly an issue here again. Again looking at data from Baseball Savant, his whiff rate on these pitches rose significantly, up from 31 percent in 2020 to 44 percent this past season. These issues are reflected in comparing his whiff rate by zone between 2020 (when he put up a 119 wRC+ in the shortened season) and 2021, where you can see a large increase on pitches out of the zone from the lower half and below.

That’s to be expected, again, based on the previous knowledge we have of Bradley’s weaknesses. What was more surprising to me in investigating his rough 2021 was some relative struggles against the fastball. Some of this does connect back to the strikeout issues, with his whiff rate against velocity coming in at 28 percent, eight percentage points above his rate in 2020. And in the graphics above, you see a stark increase on pitches up and in on the hands. That was exacerbated by a similar increase in swing rate on pitches in that zone, up to 26 percent from 15 percent.

But these fastball issues also connect back to the lack of power that he provided in Milwaukee in 2015. The batted ball numbers are a bit misleading here with Bradley, as Baseball Savant gives him a hard-hit rate of 41 percent, just a single percentage point below his career average. However, hard hits come in different varieties, and while his solid contact rate is right in line with his career norms, his barrel rate (which is the ideal kind of contact in terms of exit velocity and launch angle) was the lowest of his career and put him in the bottom 20 percent of the league.

That brings us back to the fastball, because Bradley was missing hittable pitches in the zone, and it seems like a lot of those were fastballs. Over his career, he’s always had issues with secondaries but has cleaned up on fastballs to keep his numbers above water. This past season, though, his wOBA against those offerings was just .250 with an expected wOBA (based on plate discipline and batted ball data) of .284. Prior to 2021, his career worsts against fastballs were .340 and .356, respectively. Below you can see Bradley’s average exit velocity on pitches by where they were in (or out of) the strike zone, and you’ll see that the numbers drop on pitches on the inner third of the plate.

As with most things when it comes to trying to predict the future, I think you can take the optimistic or pessimistic view of this situation with equal ease. For the pessimistic point, you can look at him always having stretches like this along with the fact that he’s getting older. Next season will be his age-32 season, and that’s typically around the time we see non-stars start to fall off. Of course, not being able to connect on pitches on the inner half can be a sign of slowing bat speed.

On the other hand, I think we’ve also seen Bradley get in these slumps before, and they often have a tendency to snowball upon themselves as he continues to press. Clearly he never really snapped out of that funk last season, but it stands to reason that returning to Boston, a place where he’s spent a ton of time and presumably feels at least some level of comfort with a coaching staff he mostly knows, can get him back in a groove.

The good news on this front is that the Red Sox don’t really need Bradley to be the guy he was in that shortened 2020 season when he was on pace for a 4.5-win pace. He’s likely to enter the season as the fourth outfielder, and in Jarren Duran the Red Sox have a ready-made replacement on the depth chart with real upside. But they know what Bradley can provide with his defense so long as he’s meeting the base requirements at the plate. He did not meet said requirements last season, and there are a whole lot of reasons why that was the case. Whether or not he can snap out of those bad habits will go a long way towards determining how solid Boston’s outfield depth really is.