Mateo is a projectable everyday major league shortstop who brings an average bat and above-average to plus defensive ability to the table, though the tools are still somewhat raw, and he still needs some polish for the profile to shine.
Mateo is a double-plus athlete all day, and a burner on the basepaths who is showing more maturity as a baserunner this year, going 28-for-32 (88%) in stolen base attempts after a 2016 campaign (also with High A Tampa) that saw him swipe 36 in 51 attempts (71%). He is double-plus out of the box, and the grade jumps to elite when you see him go from first-to-third base with speed that puts big-time pressure on defenders.
At the plate, Mateo shows quick hands and wrists, with a live bat that is presently more of a pull-oriented, line-drive swing with limited loft, though there’s enough there to project to fringy over-the-fence pop (10-to-12 home runs) at maturity. He can give away at-bats at times by leaking his front side and pulling off of pitches, which makes it tough to cover the outside half of the plate and keep the barrel in-zone for an extended period, and is a contributing factor to his high strikeout percentage (27% over 297 plate appearances) to-date.
He can also be aggressive in his approach, expanding the zone especially when chasing breaking stuff, and he will need to develop better plate discipline as he advances (5% walk rate). He does bring some pop with the bat, showing good bat speed and getting his share of extra base hits (partly attributable to the run tool), with 16 doubles and eight triples to go with four home runs, and with more seasoning he should project to an overall average hit tool.
Defensively, Mateo shows plus agility and footwork at shortstop, with quick hands and presently average fielding actions that will improve as he develops more body control. He shows good first-step quickness to have above-average range, and tops it off with a plus arm and quick release that allows him to make all the necessary throws to hold down the position for the long term. The defensive package projects to plus overall.
Mateo is an exciting player to watch, and his loose, athletic body, raw speed, and wirey strength give him the tools and ability to project to a Role 55, above-average everyday shortstop in the big leagues. He has a chance to become a Role 60 player capable of an occasional all-star appearance if he can develop more plate discipline and plate coverage and get on base more often to take advantage of his speed, which pairs quite nicely with the plus defensive profile.
Ed. Note: Mateo was promoted to the Double-A Trenton Thunder (Eastern League) on June 27.