We've known Mike Trout is a five tool player for some time, probably well before he was called up to the big league. The vaunted "five tool player" superlative has been bandied about for decades, and it's meaning is exactly as it sounds: a player who excels at five major areas of the game of baseball. Basically, it means a guy can hit, he has beefy power, sick baserunning skills and flashy speed, a cannon for an arm and a good glove to go along with it.
In the past, baseball minds have used the 20-80 scouting scale to see where a guy lands as far as having those five tasty tools(50 being the "average" score), but that was the old way of doing things.