Zack Greinke autograph: that's a weird stat to show

Finally got my hands on a Zack Greinke auto for a reasonable price (took a year to win one).  Here's the card:

Pretty nice.

I then looked at the back of the card:

Isn't that sort of a weird statistic to show?  Home Runs Allowed?  I don't have any other Topps Unique cards.  I am assuming the non-pitcher cards show a breakdown of home runs hit?  Still, strange for a pitcher card.

Oakland A's tickets went on sale this morning!