Two San Francisco 49ers players, including their longtime left tackle Joe Staley, sustained knee injuries during the team’s Sunday afternoon loss to the Los Angeles Chargers in Carson, Calif.Staley, a six-time Pro Bowl selection who is in his 12th NFL season, all with the 49ers, didn’t return after hurting his right knee in the second quarter. The injury happened when he collided with quarterback C.J. Beathard, who was throwing a pass.Staley’s injury came not long after wide receiver Dante Pettis also hurt a knee on a punt return in the first quarter. The team announced early in the second half that Pettis would not return Sunday.Head coach Kyle Shanahan offered no updates on the extent of those injuries after the game. NBC Bay Area reported that the 49ers believe Staley didn’t sustain an anterior cruciate ligament injury, but he likely will undergo an MRI exam Monday.First-year right tackle Mike McGlinchey and wide receiver Marquise Goodwin also left in the last drive of the second quarter. Different reports said McGlinchey had a knee or an ankle injury. Goodwin’s injury was not immediately reported.Also, running back Matt Breida left with what was reported to be a shoulder injury, although he returned to the game.Breida separated a shoulder in the preseason and was listed as questionable this week because of a hyperextended knee from last week’s game against the Kansas City Chiefs.