It was an eventful year for Mateo. He completely underwhelmed in a repeat trip to High-A, received a promotion to Double-A anyway, raked, got dealt to the A's, and kept raking. From a fantasy perspective, Mateo is the best prospect Oakland received in the Sonny Gray trade. He has legitimate 80-grade speed -- a tool that has allowed Billy Hamilton and Dee Gordon to not only be relevant, but coveted in roto leagues, despite posting isolated power figures that look more like fahrenheit readings. Unlike Hamilton and Gordon, Mateo is not a zero in the power department, and could pull 8-to-12 balls out per year at peak. His batting average will likely fluctuate quite a bit based on BABIP, but he could be a .250 or .260 hitter who occasionally flirts with hitting .280. Since the trade, he is back to being developed as a shortstop. He could be ready for a callup in the second half, but the A's have an annoying amount of controllable, albeit uninspiring middle infielders, so it's hard to say when Mateo will be handed an everyday gig.

Mateo had a rocky 2016, including a suspension midseason for conduct detrimental to the team. He started the season at High-A Tampa and apparently was dissatisfied with the lack of a promotion to Double-A Trenton. On the field, Mateo's average was down, his strikeouts were up, and he stole less than half as many bases as he did in 2015. He hit just .254 with 36 steals in 2016, as compared to a .278 average and 82 steals in 2015. In addition, with the acquisition of Gleyber Torres from the Cubs, the Yankees have been trying out new positions for the 21-year-old, including second base and center field. Despite the bumps in the road, Mateo's speed is elite, and he also posted career bests in home runs and RBI in 2016. He should finally get his wish and begin the 2017 campaign at Double-A, though where Mateo will play in the field remains to be seen.

A highly coveted asset at the 2015 trade deadline, Mateo was one of four Yankees prospects GM Brian Cashman deemed untouchable. At just 20 years old and never playing above the High-A level, the shortstop has already made a name for himself in the organization, both with his bat and his legs. The 20-year-old swiped 82 bags last season between Low-A and High-A while being caught just 17 times, and he posted an impressive .321/.374/.452 line once being promoted. Didi Gregorius currently poses a potential roadblock to Mateo at short at the big league level, but the youngster doesn't have any minor league experience at any other position in the field. Mateo is still at least a year away from getting his first taste of the big leagues, if not more, but should continue to move up through the organizational ranks in 2016 and could be worth a look in dynasty formats.