Jackie Bradley, Jr. demoted: What does Boston's defensive star say about Jake Marisnick

Jackie Bradley, Jr., pride of South Carolina baseball, got demoted Monday. It was a long time coming, but probably deserved.

Since the Astros finished playing Boston, this may not matter to you, dear Astros fan reader. But, it does matter in the context of Houston's own defensive whiz outfielder, Jake Marisnick.

In only 16 games, Marisnick has shown he's the best defensive outfielder on Houston's roster. But, Bradley was unquestionably the best defensive outfielder on Boston's roster and one of the best five or six defensive outfielders in the majors. Why did he get demoted while Marisnick became a key cog in a trade for a young, cost-controlled pitcher?

Let's dive into the numbers, shall we?

Jackie Bradley, Jr. amassed 18.1 Defensive "Runs" in 112 games for the Red Sox. That's not DRS, but the Defensive runs factor used to calculate fWAR for position players. Bradley was projected to finish the season with 20 Defensive runs by the end of the season.

Only 17 outfielders have totals higher than that in a single season since 2000. Andruw Jones is on the list nine times.

That's a big reason why Jackie Bradley, Jr. played in so many games, despite neither an on-base percentage nor a slugging percentage over .300. It's also why Bill Simmons (noted Red Sox fan and unreliable narrator) said he frequently wonders if JBJ needs to get his eyes checked.

In 16 games, Jake Marisnick has already racked up 3.1 Defensive "runs." Project that out over a full season of 150 games and Marisnikc would total 29 Defensive "runs."

Projections don't work like that, but there is a rough, rough, rough, ROUGH estimation at how good Marisnick has been defensively since coming to Houston. It's also why he will continue to play, even after Dexter Fowler and George Springer are both playing together again.

By Seamheads standards, Marisnick has already saved 3.5 runs above average with his range alone. As a comparison, Bradley has been worth 8.5 runs above average in range while Juan Lagares leads the majors with 16.4 runs above average. Across all his games in center this season, Marisnick has been worth 10.2 runs above average, good for fourth in the majors and two spots ahead of Bradley.

For comparison's sake, George Springer's range has been worth 2.2 runs above average and Dexter Fowler's has been worth 19 runs below average. Marisnick is clearly the best defensive outfielder on the roster. He should be playing every day.

Marisnick is a wizard with the glove, but so was Jackie Bradley.

The breaking point is the bat.

Bradley hit reasonably well in the minors. He had a .275/.374/.469 line in Triple-A last season and has a career line of .297/.404/.471 in three minor-league seasons. He's got a good walk rate in both the majors and the minors. His biggest problem? Bradley cannot make consistent contact.

His 74 percent contact rate ranks right there with Jason Castro, who's not exactly a contact maestro. Only 11 qualified batters in the majors have lower contact rates. This is not an isolated incident, either. He struck out nearly 20 percent of the time at Double-A and Triple-A combined.

For any Astros fan who has followed along for the past three seasons, contact issues like that should be worrisome.

Compare that to Marisnick. The Astros defensive whiz has a contact rate of 77 percent with the Astros and a contact rate closer to 19 percent in Double-A and Triple-A combined. With the Marlins in 2013, though, Marisnick's contact rate was at 80 percent in 118 plate appearances.

Marisnick's minor league line stands at .279/.347/.444 in five seasons. His Triple-A line this year was .277/.326/.434.

There's no question Bradley has a better minor league track record as a hitter. He's also a year older than Marisnick, which matters in minor league comparisons, but not by much.

Of course, the biggest difference right now is batting average on balls in play. Marisnick isn't the player who hit .183 with the Marlins. He's hitting .293/.311/.397 with the Astros, thanks to a .320 BABiP. Bradley had a .311 BABiP this season, when he posted an ugly 60 wRC+ before his demotion.

Bradley did have months where he looked competent. In July of this year, the Boston center fielder hit .278/.325/.347 thanks to a .377 BABiP that seemed less than sustainable.

While it's very possible Marisnick's recent hot streak at the plate is a mirage, he doesn't seem to have the same offensive problems that Bradley possesses in the majors. A terribly small sample size suggests otherwise. But, the lesson here is that Marisnick's defense will keep him in the lineup until his bat forces him out, much like what happened with Jackie Bradley in Boston.