Mookie Betts

Roster Recap: The Magnificent Mookie Betts

Welcome to BP Boston’s new Roster Recap series! Over the next four months, we’ll be breaking down every player on Boston’s 40-man roster and many of their top prospects in order to provide a comprehensive overview of the Red Sox roster’s strengths and weaknesses, as well as what we can expect moving forward. There’s no better time than the offseason to review the best (there was some best!) and worst (there was a lot of worst!) of the past year in red and navy, and what better way to lead off this series than with the team’s leadoff hitter?

Mookie Betts was one of the most compelling players on the Sox coming into 2015, poised for an emergent season after a very exciting couple of months in Boston in 2014. No matter how much Ruben Amaro wanted him, the Sox did not deal Betts for starting pitching before the season, and rolled with the diminutive hitter in center field and the leadoff spot to start the season. Things started well…

… then Mookie slumped early in the season, got injured a couple of times, got better, and finished the season with a stat line we all could get behind, posting 5.1 Wins Above Replacement Player. The hype is real, and Mookie is here to stay.*

* – Unless Dave Dombrowski trades him for a starter.

What Went Right

This part is actually fun to write, because a lot went as expected with Betts this season. I mentioned those 5.1 WARP earlier—here at BP, that translates to “this guy was basically an All-Star.”

Let’s start with his offense, which was quite good. Betts posted an OBP of .341 and a slugging percentage of .479, which would be a very nice combination for anyone, let alone a speedy, solid defender in a critical position. His True Average was .291, which was 42nd among hitters with 500 or more plate appearances this season. (To put that in perspective, Mookie was .001 lower than Alex Rodriguez, had the same TAv as Jose Abreu, and was .001 higher than Jason Kipnis.)

Betts’ approach was good, but he improved his power from previous years, muscling 68 extra-base hits: 42 doubles, 8 triples, and 18 homers. If you threw a ball over the plate to Betts, he hit it. Very hard.

Also, Betts was one of the top baserunners in baseball, despite only stealing 21 bases on the season. BP’s BRR stat, which accounts for most baserunning feats, only gives him credit for 2.3 runs, which is fewer even than he earned in his stint with the Sox in ‘14. However, FanGraphs’ BsR stat places Betts at adding almost a full win just on the basepaths, with 8.3 runs added. Most of this comes from taking the extra base and avoiding double plays—he actually tied Kris Bryant for the most runs saved via avoiding GIDPs—but his 21 steals also helped.

Did I mention he played pretty good defense in the outfield?

I don’t need to mention it, because there is video proof everywhere.

Best of all (Betts of all?), Mookie improved as the season went along. Ryan Morrison did a brilliant deep dive into his plate discipline, and noted that Mookie has some trouble hitting offspeed stuff. So what did Mookie do as the season went on? He stopped swinging at offspeed pitches. Because he’s great. The best hitters make adjustments that work. Mookie is making adjustments, and they’re working.

What Went Wrong

I’m not sure that there’s much that really went “wrong” as far as Betts goes this season. He performed for the entire year at an All-Star level of play. However, there are two things that Sox fans may want to see change going forward.

As I mentioned before, Betts saw his power spike a little in 2015. Unfortunately, along with the power spike has come some diminishing returns in terms of his formerly-prodigious walk rate. In his two red-hot seasons in the minors before his 2014 callup, Betts was a walking fiend—a tiny, magnificent Kevin Youkilis. This past season, Betts’ walk rate fell to 7.0 percent, which in turn caused his OBP to dip to .341. That’s not a bad number, but it does represent a True Average dip of .009 from last season, despite a .035 point hike in slugging percentage.

Dave Cameron noted that Mookie walked less because he was swinging at more pitches out of the zone—that isn’t where he culled his power gains from specifically (he benefitted from driving balls over the plate), but the change in approach may have helped him drive the ball nonetheless. Fans of Mookie’s famously patient approach may pine for the old minor-league walk rates in the double-digits, but it appears that his approach has shifted somewhat in his time in the bigs.

In his two red-hot seasons in the minors before his 2014 callup, Betts was a walking fiend—a tiny, magnificent Kevin Youkilis.

There’s another issue at play here that may be cause for concern going forward: Betts’ defense. First and foremost, I think that Betts is a solid defender, but his aggressiveness led to some scary moments and injuries this season. To top that off, defensive metrics gave a mixed bag of reviews to his work in the field on an overall level. Baseball Prospectus’ FRAA metric gives Betts credit for 6.3 runs of defensive value this season, which takes into account time mostly in center, but also in right. This is pretty good. Defensive Runs Saved gave Betts nine runs to the positive in the middle, four of which were due to his arm (which plays up nicely in the middle). But UZR, a component in FanGraphs’ wins above replacement metric, only gives Betts 1.5 runs to the positive.

The important thing to note is that single-season defensive metrics can fluctuate wildly, and aren’t exactly a strong reflection of true talent in a one-season sample. His Inside Edge fielding numbers—which track the likelihood of all players making a play on a ball in a particular spot in the field—actually look quite similar to Lorenzo Cain’s. So, while we may have expected Betts to be a transcendent defender in center due to his lightning speed, in truth he looked more like an average-to-good defender, depending on the metric. Boo frickin’ hoo.

Outlook for 2016

The outlook for Mookie is positively sunny, because that’s what happens when a 22-year-old puts up a five-win season. He didn’t rack up those positive numbers because of some fluke: he did so by leveraging the skills we all knew he had (speed, solid approach, surprising strength) and improving gently in the power department. I think we’d all love to see him ramp up his outfield defense to even more impressive levels and start being more selective on pitches outside the strike zone while maintaining his power stroke. Maybe he could be more consistent rather than streaky. And if he avoided running into walls, that’d be nice too.

But those adjustments I just mentioned aren’t necessary. They’re nice-to-haves. They’re the types of adjustments that turn a player from an All-Star to an MVP candidate. While we’d all like Mookie to accelerate into one of the top-10 players in MLB, he’s already a star. So long as he stays healthy and nothing terrible happens to his game, he’s perhaps the most foundational piece on this Red Sox team, and the type of player you make plans to watch for the next decade.

Photo by Greg M. Cooper/USA Today Sports Images

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1 comment on “Roster Recap: The Magnificent Mookie Betts”


Any chance Mookie ever slides back to 2B?

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