What position did Joe Mauer primarily play?

What uniform number did Kirby Puckett wear with the Twins? Harmon Killebrew is best known for playing with which MLB team? What uniform number did Harmon Killebrew wear with the Twins? Which player was nicknamed "Killer"? What uniform number did Joe Mauer wear with the Twins? Frank Thomas is best known for playing with which MLB team? What uniform number did Frank Thomas wear with the White Sox? What position did Paul Konerko primarily play?