Make that two significant injuries for the No. 2 pick. On Thursday, 49ers general manager John Lynch said rookie edge rusher Nick Bosa sustained an ankle sprain in practice Wednesday that was more severe than initially reported. Lynch said Bosa had characteristics of a high ankle sprain and suggested his availability for the regular-season opener at Tampa Bay on Sept. 8 was in question. Lynch said the 49ers would be "very prudent" with Bosa. "It's a significant ankle sprain," Lynch said on KNBR. "There's that dreaded high ankle sprain. He doesn't have a full blow one, but it has some components of that … We won't see him in the preseason and we'll go from there." Bosa has now sustained two injuries in 12 NFL practices. In May, in his second practice, Bosa sustained a hamstring injury that sidelined him for the rest of the offseason program. On Wednesday, in the 10th practice of training camp, Bosa was injured when he caught up in a pile on a running play. Bosa, whose brother, Joey, is a Pro Bowl pass-rusher with the Chargers and whose dad, John, was a defensive lineman who was a first-round pick of the Dolphins, was viewed as an unusually polished draft prospect. In fact,...