Based on what?
http://www.baseball-reference.com/minors/player.cgi?id=saltal001jar
http://www.baseball-reference.com/players/s/saltaja01.shtml
His 162 game "projection" is 21 HR.
He will not hit 30 HR, and trust me....Ive already won 2, almost 3 of these bets with a member of this board [Ross (20 this year, pending), Agon (30 last year), Agon (25 this year)].