(Santa Clara, CA)  --  49ers head coach Kyle Shanahan isn't ready to name his starting quarterback just yet.  Shanahan did say Wednesday that he has a good idea who will be under center Week One.  Jimmy Garoppolo, who appears in line to start as he enters his fifth season with the 49ers, also said Wednesday he has a "pretty good idea" who will start but will let Shanahan make the call.  The Niners open the season September 12th at the Detroit Lions.