New, improved Rusney Castillo earning his spot for 2016

The Red Sox signed Rusney Castillo to a seven-year, $72.5 million deal just about 12 months ago. At the time, the move created plenty of excitement among fans looking to find reason for hope on a last-place team. Castillo brought speed, alluring potential and the possibility of improved outfield production on a club starved of offense.

One year later, Castillo's initial playing experience stateside hasn't exactly gone as hoped. The Cuban native has played just 58 games for Boston, with nagging injuries and the necessary adjustments to American ball preventing him from making the type of impact many had expected. After a promising 10-game stint in 2014, Castillo struggled at the major league level earlier this season, leading to a demotion to Pawtucket back in June and widespread questions regarding what his ultimate future might be.

Castillo's biggest issue during his first stint with the Red Sox this year was his inability to hit the ball in the air. According to FanGraphs, he has hit 68 percent of his balls in play on the ground in 2015, a figure that ranks higher than any other batter in baseball (min. 160 plate appearances). Even for a speedy player like Castillo, that's simply too many ground balls to make much of an impact with the bat. And for their part, the Red Sox hoped Castillo would provide some power to go along with his speed and defense.

Yet since Castillo returned to the majors on July 27, the 28-year-old has made noticeable strides at the plate and begun to hit the ball in the air with greater consistency. During his initial time in Boston this season, Castillo hit .230/.260/.284 with just two extra-base hits over 77 plate appearances. Since returning to the big league club, he has batted .375/.412/.613 with nine extra-base hits (and four home runs) over 86 plate appearances. Expecting Castillo to slug over .600 the rest of the way is wishful thinking, but the renewed power and ability to feast on MLB pitching, even over a short time period, is encouraging for his future.

In addition, as Brian MacPherson detailed at the Providence Journal in early August, Castillo has made legitimate mechanical changes that have helped drive his improved performance:

The latest adjustment came just over a week ago, a tweak to the way he held his bat as the pitcher went into his delivery. Rather than hold his bat straight up and down, he now is holding the bat at more of an angle -- the better to get into his swing path more quickly than he had before.

Prior to the change, Castillo was "wrapping his bat," as Red Sox assistant hitting coach Victor Rodriguez put it, causing the outfielder to be vulnerable against fastballs, especially those on the inner half. Now Castillo's hands are taking a much quicker, more direct path to the ball and enabling him to barrel up opposing pitches more consistently.

Given that Castillo's recent success has come over a limited sample, we should be careful before declaring him as the All-Star level performer he's played like over the past 23 games. Still, improved performances become much easier to believe in when they happen in concert with genuine mechanical changes we can point to.

That Castillo has also needed to make difficult cultural adjustments off the field while playing against stiffer competition only adds to the challenges he's faced in America. Too often we ignore the lifestyle transition Cuban players must make upon arriving stateside, and it's worth remembering that Castillo has lived in the U.S. for only a year now.

The biggest question for the Red Sox and Dave Dombrowski is just where Castillo now fits into the team's outfield picture moving forward. How much stock should be put into his strong play over the past couple weeks?

There is little denying that, after a season spent watching Hanley Ramirez feign competence in left field, an outfield trio of Castillo, Mookie Betts and Jackie Bradley sounds wonderful on paper. And with both Castillo and Bradley showing improvements at the plate, that notion has only gained traction among fans in recent weeks.

But there's also a possibility that Castillo and Bradley are simply performing well over a small sample, and that the Red Sox could be stuck with two below-average outfielders yet again in 2016. For a club that's suffered from woeful outfield production for two straight seasons now, that would be a bitter pill to swallow.

The good news is that Dombrowski has another month to assess just what Castillo and Bradley are and what they can be for Boston next year (and beyond). Perhaps one or both struggle down the stretch, and Dombrowski is forced to look elsewhere for outfield help. Perhaps they build up enough trade value for the Red Sox to swing a deal involving one of them this offseason.

Or perhaps Dombrowski decides to keep both and put his faith in the Betts-Bradley-Castillo trio that looks so appealing in the present.

At the moment, Castillo's strong play is leaving open just such a possibility. How well he plays over the final month of the season will go a long way toward determining just what type of role he has with Boston in the future.