Welcome to BP Boston’s 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. You can see previous editions of Roster Recap here.
Despite his age of 28, Rusney Castillo should still be considered a member of the group of prospect-type Red Sox players for whom much uncertainty remains. The seven-year, $72.5 million contract he signed prior to the 2014 season inevitably led to high expectations, but Castillo is not likely to fill a role as a star, so those expectations need tempering. Rather the hope should be that Castillo will slot in as an everyday, above-average defender in the outfield and do enough with the bat to keep the bottom-third of the lineup moving. He is among the group of young outfielders, along with Jackie Bradley Jr. and Mookie Betts, who are expected to make another progression at the major league level this season; at the very least providing defense that could dramatically improve the run prevention side of Red Sox baseball. Castillo has a spot in the Opening Day lineup, but needs to show he can stay on the field and perform, or he will find himself with a permanent bench role while players like Chris Young or Brock Holt assume his starting job.
In two stints with the Red Sox in 2015 Castillo experienced the ups and downs typical of a player adapting to the rigors that come with life in the big leagues. He began the year at Pawtucket but was called to Boston at the end of May. This first run with the big league squad lasted only a month, as he was miserable at the plate, posting a .230/.260/.284 line (43 wRC+) in 77 plate appearances (PA). He struggled to command the strike zone, walking only three times and striking out 15 times – a ratio that is difficult to justify when paired with the absence of power Rusney showed during this stint (one double, one home run).
His next opportunity in the big leagues came after the Red Sox traded Shane Victorino to the Angels at the end of July, which created an opening for Rusney in the previously crowded Red Sox outfield. This second stint involved two oddly disparate months. In the first, Castillo met some of those high expectations that came with his contract. He played solid defense – other than that embarrassing in-game lapse — – and showed real ability with the bat in his 102 trips to the plate, hitting .333/.366/.531 (142 wRC+). He still had an ugly walk to strikeout ratio (5:22), but his line included four home runs, two triples, and three doubles, so the poor plate discipline was playable. Then, from September 1 through the end of the season. Rusney’s performance cratered. He managed only a .194/.236/.252 line and a 27 wRC+ in 110 PA,) appearing to have reached a physical limit in dealing with the long season. It was a rough finish to a generally inconsistent season.
What Went Right in 2015
As I mentioned in my recap of Matt Barnes’ season, the value of gaining experience is often overlooked. But for players like Rusney Castillo, who is still adapting to life in the United States and learning first-hand the conditioning required to sustain performance across a big league season, it is imperative. Gaining close to 300 PA against major league-quality pitching, playing the outfield in multiple major league parks, and developing a better understanding of how (and when) to deploy his remarkable athletic ability on the basepaths should all benefit Castillo in 2016.
Beyond experience, the best thing about Castillo’s 2015 season was undoubtedly his defense. While he struggled to a below-average performance at the plate (72 wRC+, .213 TAv), Castillo provided above-average defense in right field. According to FanGraphs’ UZR/150, among fielders with at least 350 innings at any position, his work in right field made him the eighth-best defender in baseball in 2015. Changing up the conditions a little bit to look only at outfielders with at least 600 innings (combined across left, center or right field), reveals that Rusney was the fifth-best outfielder in the game in 2015. For reference, Castillo’s 19.2 UZR/150 trailed his defensive-standout teammate Bradley Jr. (third best) by only three runs. To be clear, Rusney rated as above-average in the corners, where he spent the majority of his innings, but below-average in center. The sample of innings in center is far too small to make any bold statements, but the good news is that with Bradley Jr. and Betts on the roster, Castillo will be primarily called upon to play a corner spot in 2016.
Rusney can run down flies and has an arm that should keep baserunners in check:
What Went Wrong in 2015
As I have noted, Castillo’s major issue last year was on offense, specifically struggling to control the strike zone. His .288 on-base percentage, over 30 points lower than league average, really jumps out as an area of concern. Earning bases on balls was not really in Rusney’s repertoire last year. Among the 311 hitters with at least 250 PA in 2015, Castillo’s walk-to-strikeout ratio of 0.24 ranked 48th-worst. There are only a few players at that end of the scale who performed at an above-average level on offense. Rusney’s inability to draw walks stems from his propensity to swing and miss. He took a hack at over half of the pitches he saw last year, which was well above the typical rate, but he made contact at a rate that was below average. That is an awkward combination to try and succeed with.
One thing that has interested me for a while is what how a pitcher attacks a hitter tells us about what the pitchers (and perhaps the league in general) think about the hitter. Rob Arthur of FiveThirtyEight (previously of Baseball Prospectus) introduced this idea. Ben Lindbergh (also previously of Baseball Prospectus) also wrote an article outlining this type of analysis. You can and should read their work, but the basic idea is that if pitchers attack a batter with a lot of pitches in the strike zone, and specifically close to the center of the zone, it suggests the pitchers think the batter is an easy out. Conversely, throwing away from the center of the zone suggests they are concerned with the batter’s ability to do damage.
Well, pitchers did not shy away from throwing pitches in the strike zone to Rusney last year. By PITCHf/x data, close to half (49.3%) of the pitches thrown to Rusney were in the strike zone, which was considerably higher than the typical rate for non-pitcher batters in 2015 (47.6). So it would seem that pitchers are telling us they felt Rusney was not all that much of a threat. Looking at his zone profile confirms pitchers were willing to attack Rusney within the zone, even frequently middle-middle, but they also exploited his free-swinging tendency with breaking pitches low-and-away. A more granular look at these data would provide more insight, but it does not look like pitchers were too worried about Castillo. He will need to improve his plate discipline if he is going to be a productive major leaguer beyond the defensive side of the game.
Finally, baserunning. It would be nice if in those few times when Rusney manages to get on-base he can also manage not to run into an out. He was caught stealing in five of his nine attempts last year, which tied him for the second-worst success rate among hitters with 250 PA and nine attempts. The fact that Castillo and 33-year-old catcher Russell Martin attempted to steal the same number of times and were equally successful last year is not something I ever expected to write. Improving his decision-making on the bases should be another area of focus for Rusney heading into the 2016 season.
Outlook for 2016
His performance in 2015 makes projecting Castillo’s 2016 difficult, but he did play excellent defense and had stretches where he was more than capable at the plate. Sounds similar to Jackie Bradley Jr., no? Castillo’s durability remains a concern, but that is part of his ongoing adaptation to major league life and with Young and Holt on the roster, John Farrell can get Rusney the rest he needs to ensure he performs well throughout the year. When all is said and done, Castillo is most likely going to be a strong-glove, weak-bat, one- to two-win everyday player that will help the Red Sox compete for top spot in the division. If he and Bradley Jr. continue their defensive prowess but boost their offensive output even just a little bit this team could be really frightening. That may be asking a lot, but Castillo’s evolution will certainly be interesting to watch.
Photo by Winslow Towson/USA Today Sports Images