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. Read Past Outlooks