The San Diego Chargers join the rest of the NFL this week in opening up training camps nationwide. Even though the Chargers camp will be closed to the public (except for three open sessions at Qualcomm Stadium), there is much to be excited about this season. On a down note, the Chargers noted recently that their training camp will for the most part be closed to the public due to a public safety issue. The Murphy Canyon site was damaged earlier this year by a drainage pipe that burst, leading to a 40-foot-deep, 30-foot-wide sinkhole. While the Chargers say the sinkhole has been filled, team officials also note that there is no guarantee the ground along it or around it is safe to tread on. While the Murphy Canyon site is closed to the public for workouts, the Chargers will hold three practices at the “Q” in August: Aug. 5, 8 and 12. Those sessions will be free and open to the public. Sizing up the 2009 team, San Diego will look to a healthier LaDainian Tomlinson (1,110 yards and 11 TDs in 16 games on the ground last season), Darren Sproles (nearly 700 yards rushing/receiving), QB Philip Rivers (4,009 yards passing, 34 TDs) and wide receiver Vincent Jackson (1,098 yards receiving, seven TDs) to lead the way. On defense, linebacker Shawne Merriman returns after playing in only one game last season due to surgery, while the Chargers look to cornerback Antonio Cromarte to return to his 2007 form when he picked off 10 passes (two interceptions in 2008). In the meantime, the countdown is on until Saturday, Aug. 15, when the team hosts former AFC Western Division rival Seattle in the pre-season opener. Chargers’ first four games: • Week 1, Sat., Aug. 15, Seahawks 7 p.m. • Week 2, Sat., Aug. 22, @ Cardinals 7 p.m. • Week 3, Sat., Aug. 29, @ Falcons 5 p.m. • Week 4, Fri., Sept. 4, 49ers, 7 p.m.