You can just change the "Split" field on the leaderboard to "Live Stats - Full Season"
http://www.fangraphs.com/leaders.aspx?pos=all&stats=bat&lg=all&qual=y&type=8&season=2015&month=33&season1=2015&ind=0&team=0&rost=0&age=0&filter=&players=0
Bryce Harper just a few hundredths of a win ahead of Donaldson for most in the league. Not that such a small difference should be given meaning, just that it would be fun seeing Donaldson on top.