San Francisco Giants backup catcher Tom Murphy will get an injection for a herniated disk in his back that will sideline him for at least two weeks, and could keep him from being ready for the start of the season. "It's going to be a couple weeks of inactivity, strengthening, stuff like that," manager Bob Melvin told reporters at the Giants camp Monday. Melvin said it was a definite possibility that Murphy won't be ready for opening day March 27 at Cincinnati.