Possible Clues:

• Twain, really
• Twain, actually
• Samuel Langhorne --, real name of Mark Twain
• American League MVP after Mattingly
• Baseball's Roger
• U.S. Grant's publisher
• General Grant's publisher
• Only starting pitcher since 1971 to win a league M.V.P. award
• Samuel Langhorne ___
• Finn's Samuel Langhorne