Mateo is slashing just .196/.237/.297 with 15 extra-base hits (nine doubles, six triples) over 225 plate appearances across 58 games at Triple-A Nashville.
The six three-baggers certainly is an eye-opener, but there's not much else to write home about with respect to Mateo's body of work with the Sounds thus far. After posting .300 and .292 averages, respectively, over a pair of Double-A stops in 2017 with the Yankees and Athletics organizations, the 22-year-old has found Triple-A arms exceedingly difficult to solve. That might be best summed up in his strikeout rate, which has climbed to a career-high 30.2 percent in Nashville, a near-eight-point boost from the 22.4 percent figure he'd generated at Double-A Midland last season. With Marcus Semien playing on just a one-year contract and arbitration-eligible in 2019, there was hope that Mateo could potentially be ready for a promotion by the end of this season. However, if his current numbers are any indication, he'll need substantially more seasoning before that can be realistically considered.