Possible Clues:

• Baseball's Wagner
• Wagner in Cooperstown
• Baseball Hall of Famer Wagner
• Wagner whose baseball card sells for millions
• Wagner on a very valuable baseball card
• Cooperstown's Wagner
• Baseball Hall-of-Famer Wagner, one of the first five inductees
• Wagner of baseball
• Fellow shortstop of Cal and Ernie on baseball's All-Century team
• ___ Wagner, player on an ultrarare baseball card