Scouting Miami’s Return for Marcell Ozuna by Eric Longenhagen December 14, 2017 The Miami Marlins received a quartet of prospects – OF Magneuris Sierra, RHP Sandy Alcantara, RHP Zac Gallen, and LHP Daniel Castano — from St. Louis in exchange for All-Star outfielder Marcell Ozuna on Wednesday afternoon. Sierra and Alcantara ranked fourth and fifth, respectively, on our recent Cardinals farm system audit, while Gallen ranked 18th. Castano didn’t make the list, which has full reports regarding everyone I discuss below. Alcantara reached the majors in 2017 but had a somewhat disappointing season, posting a 4.44 ERA at Double-A and a lower strikeout rate relative to his 2016 numbers. He throws hard, 95-99 as a starter and 98-101 in relief, and had one of the more promising curveballs in the minors entering this season. But Alcantara’s repertoire was tinkered with this year. Though he was throwing the curveball early in the season, it was scrapped in his major-league appearances in deference to a mediocre slider, perhaps because Alcantara was exhibiting a higher arm slot when he threw his curveball. In his 2017 Fall League run, Alcantara was utilizing both a curve and slider, though neither was very good. His changeup, which projects to plus, is now his best secondary pitch. It’s possible that Miami’s player-development staff can now take the time to push the reset button on Alcantara’s curveball. If he looks like 2016 Sandy Alcantara (elite velocity, plus curveball, and changeup projection) then his future is brighter than it would have been in St. Louis, where he was likely ticketed for the bullpen immediately. He’ll have to continue to polish his ability to throw strikes to avoid that outcome in Miami, but he’s likely to be some kind of valuable big leaguer, whether as a lights-out bullpen arm (if his secondaries and command never develop) or an All-Star rotation piece if they do. Magneuris Sierra also made his major-league debut in 2017, jumping straight from A-ball to St. Louis early in the year. He began his career with a nine-game hit streak but had an unproductive September due to limited playing time. I’ve gotten mixed reports on Sierra’s defensive instincts, but scouts agree that his plus-plus speed should allow him to become at least an above-average defender in center field. His most ardent supporters believe he could be an elite defender and perennial Gold Glove contender. Much of Sierra’s ability is derived from his speed, which not only makes him a promising defensive prospect, but makes his small-ball offensive approach viable. Sierra is a slasher who peppers the baselines with weak, low-lying contact. He accrues many infield hits because of his speed, something with which he’ll have a tougher time against big-league defenses. He projects to hit for very little game power in the big leagues, and I’m not optimistic about his ability to hit for a high average, nor reach base at a high clip because of his lack of pop. But if Sierra turns into the defender many expect him to become, he’ll still be an average everyday player. Zac Gallen is an advanced righty with command of a bevy of fringe-to-average pitches. He’ll touch 95 but sits mostly in the low 90s with and average changeup, fringe curveball, and fringe cutter. Gallen reached Triple-A in 2017, his first full pro season, and projects as a fifth starter. He, Alcantara, and Sierra could all wear Marlins uniforms at some point in 2018. The final piece of the deal is Daniel Castano, a fairly athletic, 6-foot-4, 230-pound lefty who had a 2.57 ERA at short-season State College in 2017. He was a 19th-rounder out of Baylor in 2016 and thus old relative to most prospects at that level of the minor leagues. Castano posted a 51% ground-ball rate thanks to the plane created on his fastball by his overhand arm slot. He has fringe velocity, an average changeup, and a well-below-average curveball. He’s a long-shot flier with an interesting skill.