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The 25-year-old Gonzales is only just making his way back from a pair of injury-plagued seasons. Gonzales missed a good chunk of 2015 due to shoulder problems and then all of 2016 due to Tommy John surgery. The southpaw posted a 2.90 ERA, 3.35 K/BB rate and 7.5 K/9 over 11 starts and 68 1/3 IP at the Triple-A level this season, and Gonzales made it back to the big leagues for one start this season, a 3 1/3-inning outing on June 13.
St. Louis drafted Gonzales 19th overall in 2013 and both Baseball America and Baseball Prospectus ranked him as one of the top 52 prospects in the sport prior to the 2015 season. BA ranked him as the #1 prospect in the Cardinals’ farm system that year, giving particular praise to Gonzales’ outstanding changeup. The Cardinals thought enough of Gonzales that they promoted him to the majors barely a year after drafting him, and the lefty even made the Cards’ postseason roster in 2014, not allowing a run in five of his six outings in the playoffs.
Seattle was known to be looking for young pitching, and while Gonzales doesn’t project as an immediate upgrade for the current M’s rotation, he still possesses quite a bit of upside. Beyond his potential on the mound, Gonzales also offers over six remaining years of team control; he isn’t eligible for arbitration until after the 2020 season, and won’t be a free agent until after 2023. With Drew Smyly scheduled to miss most or all of 2018 recovering from Tommy John surgery and Hisashi Iwakuma and Yovani Gallardo both questionable to have their club options exercised for next season, Gonzales projects to be an important rotation piece for the 2018 Mariners.
In acquiring Gonzales, the M’s gave up a well-regarded young player in O’Neill, who was comfortably positioned within preseason top-1oo prospect lists from MLB.com (36th), Baseball America (38th), Baseball Prospectus (53rd). Power is O’Neill’s calling card, as he has 89 homers over 1794 minor league plate appearances, including 19 this season at the Triple-A level. O’Neill got off to something of a slow start in his first taste of Triple-A action, though he has recovered to post a .244/.328/.479 slash line through 396 PA. He has cut down on his strikeouts over the last two seasons, though he still gets more than his share of whiffs, with 108 strikeouts this season. O’Neill’s plate discipline and average corner outfield defense are also works in progress, though the 22-year-old Canadian has so much raw power and overall hitting potential that the Cardinals are surely willing to tolerate some growing pains.
O’Neill joins several other interesting young outfielders in the St. Louis farm system, and USA Today’s Bob Nightengale speculates that the Cards could now look to move an outfielder from their MLB roster in the offseason. This could imply that Randal Grichuk or Stephen Piscotty could become trade chips, though the Cardinals would be selling low on either player in the wake of lackluster 2017 seasons.