What position did Jake Arrieta primarily play?

Salvador Perez is best known for playing with which MLB team? What uniform number did Salvador Perez wear with the Royals? What position did Mike Mussina primarily play? Which player was nicknamed "Moose"? Jake Arrieta is best known for playing with which MLB team? What uniform number did Jake Arrieta wear with the Cubs? What position did Zack Greinke primarily play? What position did Luis Gonzalez primarily play?