Ask the director of any play how rehearsals are going a week before opening night, and you will hear shrieks that sound something like, "Gaaaaaaa!" Baseball teams are the same way. Twelve days before the Giants open defense of their World Series title in Los Angeles, the champs have a lot of pieces out of place. Their No. 3 hitter, Pablo Sandoval, will not throw a baseball before this weekend because of an inflamed ulnar nerve in his right elbow. Head athletic trainer Dave Groeschner revealed Tuesday that an MRI taken Monday also shows a bone spur in the back of Sandoval's elbow, which Groeschner downplayed as a "chronic" condition that should not prevent the third baseman from playing. Two of the three left-handed relievers, Jose Mijares and Javier Lopez, are behind after getting hurt, with Lopez ahead of Mijares on the comeback trail. Angel Pagan, the Giants' center fielder and leadoff hitter, and reliever Santiago Casilla probably will not rejoin the team until Thursday after playing in the World Baseball Classic. Most troublesome, backup catcher Hector Sanchez is struggling through his second spring bout of shoulder inflammation and will attempt to play light catch Wednesday. Of all the injured Giants, Sanchez is the most iffy for Opening Day, which has big implications for a team that likes to get Buster Posey out of the squat once every four or five games.