Possible Clues:

• It's serious when opener's out, having score less than a hundred
• Cardinal having great influence, not weak
• A score less than century, important after loss of first wicket
• Mercury's atomic number
• A speedster may do it
• Number retired for Steve Largent and Jerry Rice
• 'Nineteen -- Four' (novel)
• Year in which the Colosseum opened
• San Francisco-to-Salt Lake City interstate
• Days needed to travel the world?