Back when the Tampa Bay Rays traded James Shields and future cyborg Wade Davis to the Kansas City Royals, the biggest piece that came back was Wil Myers. He was a top prospect, an excellent power hitter who appeared as though he could become a franchise player. He certainly fulfilled that promise in his first season with the Rays, winning the Rookie of the Year award while producing a .293/.354/.478 batting line and hitting 13 homers.
Yet, even that year, there were concerns. Myers struggled in the second half, as pitchers figured out that his open stance left him susceptible to pitches that broke down and away.