Xander Bogaerts isn't done developing yet

Many view 2015 as the year that Xander Bogaerts finally turned his sky-high potential into reality for the Red Sox. Entering the season as a big question mark, Bogaerts was one of Boston's best players, with his strong play on both offense and defense solidifying his standing as the team's shortstop for years to come.

At the age of 22, Bogaerts batted .320/.355/.421, posted a 109 wRC+ and compiled 4.6 bWAR over 654 plate appearances. His rapid improvement from the year prior, in which he stumbled to a wRC+ of 82 and struggled with the glove, was perhaps the most surprising part of his impressive campaign. To all the world, Bogaerts' 2015 season looked like a classic example of a future star turning the corner at the major league level.

All of which means Bogaerts will only get better in 2016, right?

Not necessarily. Although Bogaerts' season had the look of a breakout, a closer glance at his performance indicates he is still very much developing and honing his approach at the plate.

As many pointed out this summer, Bogaerts took an aggressive strategy against opposing pitchers last year. He wasn't afraid to swing early in the count and was even less fearful of using the whole field, often going the other way to pick up easy base hits.

Source: FanGraphs

While he used this approach to great success, such a tactic is less likely to pay off so considerably in the future.

For one, Bogaerts' .372 BABIP was among the highest in MLB last season, and though his tendency to hit line drives and groundballs in bunches means an above-average BABIP shouldn't surprise us, it's unlikely he again posts numbers so far above the league norm.  That he combined this with an exceedingly low walk rate of 4.9% also shows how much he benefited from good fortune on balls in play.

For a hitter who routinely posted walk rates approaching 10% in the minors, that's quite the changed profile. And for a youngster whose power potential at shortstop made him such a noteworthy prospect, Bogaerts' seven home runs and .421 slugging percentage also come as a surprise. His decision to trade power for contact led to big improvements in 2015 but also demonstrates that Bogaerts' skill set is still in flux, his maturation at the big league level still ongoing.

None of this means we should alter our expectations for what Bogaerts can ultimately become. The most encouraging thing about Bogaerts is that he is only 23 years old and will be entering his third full MLB season this spring. There is plenty of time for Bogaerts to continue tinkering with his approach and for him to tap into that power, which he showed in flashes last season.

His performance with the bat in September, when he recorded a higher walk rate and slugging percentage than any other month in 2015, provided an intriguing preview of where Bogaerts' development could take him next. That his output at the plate improved with throughout last season is only more promising:

This is a young player with great physical gifts and a preternatural ability to make adjustments and rapidly improve against competition well beyond his years. Given how well he bounced back from a disappointing rookie campaign, Bogaerts' capacity for continued progress shouldn't be underestimated.

His strides with the glove this past year, at the very least, ensure he'll remain at shortstop for the time being. And considering how much room to grow he has on offense, Bogaerts' ceiling remains one worth dreaming on, though there are adjustments left to be made.

What Bogaerts' 2015 demonstrates is how much of a player's development continues at the major league level. Although we like to believe a player's growth is linear, that his production will simply improve year-to-year, it's rarely quite that simple, and Bogaerts is a prime example of this reality.

There's a chance Bogaerts keeps progressing rapidly and makes these words of caution look silly next summer. For players this talented, sometimes things simply do just click into place.

Yet despite all that success last season, Bogaerts still has adjustments to make on offense, even if his future remains as bright as ever. How Bogaerts alters his approach next year - and how much he trades power and patience for contact -- will be one of the most fascinating Red Sox storylines in 2016.

Bogaerts sure looked like an All-Star shortstop for much of last season, but he's far from a finished product. For Boston, that's likely something to be encouraged about.