Never really all that good,Theriot's offense has not been the same since he left Wrigley Field where he OPSed nearly 100 points higher at home. In the last three years he has OPSed .712, .633, and .662. Scutaro in that time has OPSed .789, .721, and .781.
Defensively, Scutaro is a much better defender. The Cardinals tried Theriot at shortstop, but he was terrible. They didn't really start playing well as a team until they moved him out and put aging Furcal there. Theriot ranked at the bottom or near the bottom in every defensive metric last year for shortstops.
Theriot is more Don Buddin than Marco Scutaro.