Recent weeks haven't necessarily been all peaches and cream for the 49ers.Top wide receiver Michael Crabtree blew out his Achilles' tendon and will likely be lost for most (if not all) of the 2013 season. Quarterback Colin Kaepernick created a buzz in the media and with some fans for posting a picture of himself wearing a Miami Dolphins hat. Linebacker Ahmad Brooks was involved in an off-the-field incident with a teammate that sparked a police investigation (which led to no charges being filed). And, a recent trade for Tampa Bay cornerback Eric Wright (whose character also had come under scrutiny because of some incidents) was voided because Wright failed his physical.But beginning Thursday, all those items take a backseat. With 49ers veterans scheduled to report Wednesday to summer training camp in Santa Clara to join the rookies who reported last Friday, the Niners will hold their first full-squad practice Thursday. And for head coach Jim Harbaugh, it means a rebirth.Mr. Enthusiasm, who still carries around the disappointment of a close loss to the Ravens in the Super Bowl in February, begins a whole new season. Five months of personnel moves, minicamps, conditioning and...