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A Sabermetric Look At JBJ's Free Agency

Jackie Bradley Jr. remains unsigned as of the time of this writing, and although there are plenty of teams seeking an outfielder, no team seems to be aggressively chasing after JBJ. However, there are lot of reasons to sign him, at least when you take a dive into the swirling pool of sabermetrics. Let’s take a look at why he could be a steal for whichever team signs him, and make an attempt to project his performance in 2021 and beyond.

The first thing that stands out is how Bradley Jr. adjusted to fastballs in 2020. Pitchers threw him a steady diet of 4-seam fastballs in 2020, as nearly 40% of the pitches he saw in 2020 were of that variety. That was normal for JBJ, as he has seen more than 33% 4-seam fastballs for his entire career. But what was different was how he handled the 4-seamers that he saw. Bradley Jr.’s wFA/c on 4-seamers from the 3 years before 2020 was 1.26, which was more than twice as low than the 4.05 he put up in 2020. To sum it up, wFA/c measures how much better you were against the average MLB hitter at hitting 4-seam fastballs in any given year, negative numbers being below average and positive numbers being above average. You can learn more about this stat in this Fangraphs post by Steve Slowinski, who explains it very well. But the fact that JBJ seemed to click at hitting heaters in 2020 provides optimism that he will continue to hit for a high average in the future, and his .283 AVG, which was the highest of his career, was not a fluke. Another more common stat that shows how much he improved at hitting the fastball was his run value,. On 4-seamers in 2020, Bradley Jr. had a run value of 15, the highest he’s had on any pitch in his career. His average run value on fastballs from 2017-19 was an abysmal -1.33, which was 16+ points worse than his value from 2020 alone.

But all upward-pointing stats could have a catch, and for Bradley Jr., it’s the location of the fastballs he was thrown in 2020. If JBJ was thrown way more fastballs down the middle than in recent years, that could obviously be used to describe why he hit so much better off of them. But looking at Bradley’s Baseball Savant Illustrator pitch map from 2020, JBJ was actually thrown less fastballs down the middle of the plate than he had been in the last 3 years before the shortened season. 7.9% of the four-seamers Bradley Jr. saw in 2020 were down the middle zone of the plate, and from 2017-2019, that number was actually higher, rising to 8.3%. The fact that he wasn’t thrown a whole ton more pitches down the middle in 2020 validates his newfound ability to hit fastballs, and so does his K%. He had a K% of 20.6% on four-seamers in 2017-19, and he reduced that number by nearly 50% in 2020 to 10.8.

Since fastballs are such a large part of the pitches he sees, the fact that he now hits them so well will make a large difference in his stats. Using this, we can tell that Jackie Bradley Jr. will likely have a good year, one that about matches or exceeds his 2020 projections, in 2021. His power has always been there, having a .412 SLG over his career, so that will likely stay about where it was in 2020. His OBP and AVG will likely fall a few percentage points given that he could be in a new league facing new pitchers after free agency, so those stats will fall slightly. But overall, JBJ will have a good year, with good defensive play in the outfield as always.

2020 Stats: .283 AVG, .364 OBP, .450 SLG

2021 Projection: .275 AVG, .350 OBP, .450 SLG

All stats from baseballsavant.mlb.com, fangraphs.com.