Shortstop might not be all Brandon Crawford's job, after all.The Giants signed veteran middle infielder Ryan Theriot to a $1.25 million contract, plus $750,000 worth of possible incentives. Officially, he's a backup and Crawford is the starting shortstop.But obviously the Giants wanted an insurance policy in case Crawford crumbles.All they had in reserve before the Theriot signing were Mike Fontenot and Emmanuel Burriss. The insurance policy with Theriot is especially handy against left-handed pitchers. Crawford swings left-handed and often looked lost last year against lefties. Fontenot swings left-handed, too. It seems unlikely Crawford, Theriot, Fontenot and Burriss—along with starting second baseman Freddy Sanchez—all will make the...