49ers’ McKinnon, Williams, Verrett in danger of missing season opener

Nick Bosa has company. The rookie edge rusher with a severe ankle sprain isn't the only notable member of the 49ers in danger of missing the regular-season opener on Sept. 8 at Tampa Bay because of injury. On Thursday, head coach Kyle Shanahan said running back Jerick McKinnon (knee), first-string nickel cornerback K'Waun Williams (knee) and cornerback Jason Verrett (ankle) would miss the preseason and their status for Week 1 was uncertain. Williams recently had arthroscopic surgery and Verrett sustained an ankle injury in practice Wednesday. Meanwhile, Shanahan said McKinnon had "a lot of soreness" in his surgically repaired knee after he participated in two practices after he was taken off the physically unable to perform list Tuesday. McKinnon only participated in individual drills during his practice this week. Shanahan said McKinnon will have a plasma-rich platelet injection in his knee that will keep him out of practice for the next two weeks. McKinnon, who sustained a torn ACL just over 11 months ago, had what general manager John Lynch termed a "flareup" in his knee before training camp. The 49ers signed McKinnon to a four-year contract last year with $18 million...