Ynoa was once one of the most promising prospects ever to come out of the Dominican Republic, signing with the Athletics for a then-record $4.25MM back in 2008. He rated as the game’s No. 54 prospect the following offseason, per Baseball America, but he never delivered on that considerable potential. Elbow soreness and tendinitis wiped out his first year as a pro, and that was followed by Tommy John surgery a year later. Upon returning, he delivered mostly middling results in the Athletics’ minor league system.
Now 25 years of age, Ynoa made his MLB debut with the Sox last year, pitching to a 3.00 ERA in 30 innings but limped to a 5.90 mark through a nearly identical sample size of 29 frames with the 2017 Sox. He’s shown some ability to miss bats, but control has been an issue for Ynoa, who has a 53-to-39 K/BB ratio through his 59 Major League innings to date. He also experienced a significant dip in fastball velocity this season (though he still averaged 92.4 mph), while each of his strikeout, walk, home run and grounder rates trended in the wrong direction.