One Big Question: Can we expect Xander Bogaerts to maintain his power gains?

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 overarching question for each player heading into the coming season. We’ll go one-by-one alphabetically straight down the roster, and today we talk about Xander Bogaerts.

The Question: Was the 2018 Xander Bogaerts the real Xander Bogaerts?

I kind of hate the question of whether or not a player’s performance was real or not, which is kind of silly because I’m the one who wrote that question. I could rephrase it, but it feels apt. Still, in a sense the answer is always obviously yes. We watched it happen. It’s in the record books. Baseball-Reference has recorded the data. There’s no evidence clone created in a lab played baseball. It’s real. It’s indisputable. On the other hand, the answer is always obviously no. Players don’t have the same season year after year. They are humans who are always evolving, changing and being subjected to new outside factors. Nothing is real in the sense that you are going to see the exact same thing again. If that’s how this worked, no one would watch. So, yeah, I hate my own question that I could change but am not going to. Just a quick peek into my stupid brain.

Anyway, we should probably get to the task on hand. Xander Bogaerts. He’s pretty good! The Red Sox were defined, in the regular season at least, by their tremendous star power, and their shortstop was only a tier below MVP candidates in Mookie Betts and J.D. Martinez. In 2018, Bogaerts had the “breakout” we were all waiting for ever since he first got the call to the majors back in 2013. I put “breakout” in quotes because, of course, he has always been a damn good hitter. It’s just that he wasn’t the kind of hitter we had expected from the former top prospect and, frankly, his contact-oriented style had a limited ceiling compared to his perceived potential as a teen. Last summer, he hit like we all knew (read: hoped) he could and all wanted him to, and it was glorious.

Photo by Ezra Shaw/Getty Images

I think it’s easy to discount how good any non-Betts/Martinez hitter was for the Red Sox because those two set impossible standards for the rest of the lineup. A league-average hitter looks like garbage next to them. Bogaerts was much better than league-average, though, finishing the year hitting .288/.360/.522 for a 133 wRC+, meaning he was 33 percent better than the league-average hitter. Prior to that year, his previous career-high in wRC+ was 114. What stood out the most, and what I was alluding to above with respect to his changed style, was the power. Bogaerts hit 23 home runs (including three grand slams in 23 chances) and put up a .234 Isolated Power (SLG - AVG). Again that was easily a career-high, with his previous best ISO being .152.

It was a hell of a run and a blast to watch, but now we look forward to the coming year to see if this was a blip or something to expect moving forward. The natural, and maybe logical, first instinct is to say of course this can be expected for the near future. This was the guy we always expected, after all! He’s still only 26, in his early-prime. That’s not really something I can argue against besides by saying it’s a little simplistic. We get prospects wrong all the time, and a one-year sample confirming our old beliefs doesn’t mean we were right this time around. It also doesn’t mean we’re wrong, to be clear. It just requires a little more thought.

One Big Question: Is Mookie Betts real life?

Photo by Harry How/Getty Images

As we look at the improvements from Bogaerts, and really from all of the young hitters in the Red Sox lineup, the guy who comes up the most is the aforementioned J.D. Martinez. We all know the story by now of how he affected this lineup. His production and protection (if you buy this being a thing, at least) were huge, but his wisdom being passed on certainly came in handy, too. You saw it perhaps most prominently with Bogaerts, whose plate discipline changed his entire ability at the plate. Looking at it from a wider scope, the shortstop always had solid plate discipline. He consistently carried average-to-better-than-average walk rates along with better-than-average strikeout rates.

A lot of that was because he was such a good two-strike hitter, though. Bogaerts fell behind plenty, but he was (still is, to be fair) outstanding at playing defense at the plate and preventing easy outs. That led to low strikeout rates, but also a lot dinks and dunks for singles rather than loud contact with the potential for extra bases. With the help of Martinez and a new coaching staff, he started attacking more early in the count on pitches in the zone and was better at laying off pitches out of the zone. According to Fangraphs’ pitch discipline data, he had his highest rate of swings on pitches in the zone since 2015 and his lowest rate of swings on pitches out of the zone since 2014. Most notable was his ability to lay off the soft stuff low and off the outer-half of the plate. In the past, he’d get into zones where he couldn’t help himself on these pitches, and obviously it was tough to drive those. The zone plots below show his swing rates on pitches at different placements in the zone in 2017 compared to 2018.

All of these changes, predictably, led to better contact on a regular basis from Bogaerts. Looking at Fangraphs’ batted-ball data, he improved in every area that would be indicative of improved power numbers. He hit the ball in the air more. He utilized his pull-side more and went the other way less. He hit the ball hard more than ever, and perhaps more importantly hit the ball soft less than ever. He cut down on his pop ups. And, above all else, a higher rate of his fly balls left the yard. Sometimes this can be a fluky jump, but given all of the other factors in his favor and the fact his HR/FB ratio (15.5 percent) was still only three percentage points higher than league-average, this doesn’t seem like some sort of giant bump of luck.

If you look for yourself at all of these numbers and their changes from the past, each individual change really isn’t all that significant. It’s a few percentage points here and a few more there. Added all up, though, it’s clearly significant. On top of that, not to go all old-man-yells-at-cloud, but the eye test backed up everything the numbers say. Just watching Bogaerts it was clear that he was a new man and everything was working out for the better.

So, back to the question at hand. Was the 2018 Bogaerts real? Yes and no, as we discussed. Everything is real and also nothing is real. Can we expect Bogaerts to continue to hit for power moving forward? I would venture to guess yes. Even if there’s a slight downtick, an ISO above .200 should still be attainable and probably the expectation. If we see him flailing at the soft stuff again early in the year, we may have to reconsider that conclusion, but with him being firmly in his prime as an athlete and with Martinez and the coaching still around he should be fine. Assuming that is true, Bogaerts should be a force again, and should make himself a hell of a lot of dough next winter.