40 in 40: Jonathan Aro

Resilience is an often overlooked trait in young baseball players. We focus on physical skills and results on the field because these qualities are measurable. This is a game where a degree of failure is unavoidable though, and every once in a while, the immeasurable resilience of a player will help him overcome all obstacles. This intangible characteristic has lasting effects on their work ethic, personal drive, and ability to manage failure. Many prospects develop these skills as they encounter their first real challenges in the minor leagues. For Jonanthan Aro, resilience is just another tool in his toolbox.

While growing up in the Dominican Republic, Aro idolized the great Pedro Martinez. By age 17, he had drawn attention from a few scouts, but the reality of living in a tropical nation caught up to him. Aro was hospitalized after contracting dengue fever on two separate occasions and he nearly quit playing the game he loved. After recovering, he returned to the mound, and worked to fulfill his dream. In 2011, at the very advanced age of 20, he signed with the Boston Red Sox for $10,000. Considering that most prospective major leaguers in the region sign at 16, it's a small miracle anyone grabbed him at all.

To say that Aro was a longshot would be a gross understatement. His fastball was unimpressive and his breaking ball needed work. The scouting report listed him at 6'1" and 175 lbs, which is slight, even for a player possibly still recovering from going two rounds with that darn dengue fever. Despite all of the odds stacked against him, he succeeded in his first taste of professional baseball. Astonishingly, just four years after signing, he made his major league debut in June of last year. The official PawSox Blog had a great profile of Aro, including an interview with him after he made it to the bigs, relating his story of adversity and perseverance:

"[Recovering from dengue fever] definitely gave me a different perspective. I had to give up baseball for two years, I couldn't practice because my health was so bad. I thought I wouldn't play again, so I started studying to become a doctor, but someone told me I could do it. They told me I had the heart to be a ballplayer."

His best skill has been his ability to limit walks. In his first year in pro ball, he faced nearly 200 batters and walked just four of them. After two more years in the lower levels of the Red Sox system, something clicked, possibly stemming from the development of a reliable third offering, a tailing changeup with late dropping action. His strikeout rate jumped from 22.4% in Low-A in 2013 to 27.6% between Single-A and High-A in 2014. His improved ability to generate whiffs came at the cost of a few more walks, but his newfound success turned some heads. He started 2015 in Double-A but quickly earned a promotion to Triple-A, where he kept the strikeouts while reducing his walk rate towards his previous norms. His brief time in the majors was mostly forgettable but he clearly figured something out and impressed all the right people in Boston's organization.

Aro throws three pitches, a fastball that reaches 95 mph, a solid-average slider, and a promising changeup. In the minors, he pounded the strike zone with his fastball and used his developing slider to put batters away. He has some natural deception in his delivery, which helps his fastball play up from its average velocity. In a story from the Boston Globe, Red Sox pitching coordinator Ralph Treuel commented on Aro's mechanics: "He gets a good angle because he stays sideways longer. He has a relatively compact delivery. The ball gets on you. The hitter picks it up a little bit later than they do some other guys."

But it may be the third pitch in his repertoire that holds the key to propelling his career forward. There were 409 right-handed pitchers in the major leagues who threw at least one changeup in 2015; the horizontal movement on Aro's was sixth highest. When batters swung at the pitch, they missed almost half the time. He threw just 32 of them, so we're working with the smallest of sample sizes, but the promise is tantalizing.

Facing incredible adversity and overwhelming odds, Aro has realized a dream that ends in failure for so many others. His story is inspiring and enriches the fabric of this great game. He's listed ninth on the official depth chart and his odds of making the 25-man roster out of spring training are pretty long. But that hasn't stopped him from impressing in the past and I wouldn't be surprised to see him in a Mariner uniform sometime in 2016.