One of the statistics featured on the site is something called "Similarity Score," invented by Bill James several years ago to show players who have had similar careers. A detailed explanation can be found here.
You can compare players over their whole careers, or just through a certain periods. If you compare Trout's numbers at age 22 to other players in the middle of their age 22 seasons, you get quite a top 10. A look, in order of most similar:
1. Frank Robinson
2. Mickey Mantle
3. Orlando Cepeda
4. Al Kaline
5. Jimmie Foxx
6. Vada Pinson
7. Ted Williams
10. Tony Conigliaro.
In short, seven Hall of Famers, one guy (Griffey) who will go in as soon as he is eligible, one guy who was on his way until his career was ruined by a beaning (Conigliaro), and one guy who had a solid career (Pinson).
But it's four of the names on the list that are especially intriguing: Robinson, Mantle, Williams and Aaron. They're four of the greatest of all time, and right now, Mike Trout's name is among them.