Ryan Stewart Theriot (; born December 7, 1979) is a former Major League Baseball shortstop and second baseman.
A shortstop in college, Theriot was converted to second base for his major league debut, but played shortstop throughout the 2007–2009 seasons.
Theriot then was switched back to second base to make room for the rookie Starlin Castro, who took his spot at shortstop on May 7, 2010.
Theriot also played third base, right field, and left field.