Because that's what we call him, and that's what his teammates call him, because that's his name.
When your first name starts with not one, but two A's, and your last name starts with RON......there is no doubt what your first love will be. Even though you pitch, you are an awesome third baseman.
A-Ron is a power hitter scoring runs, the name and reputation stands. And even though he plays football and basketball.....he continues with baseball practically year round.
Of course his mom is his biggest fan who travels with the team when they go to weekend tournaments.
She helps with the scoreboard, even if it interferes with her texting.