Nick Bosa (Photo via Reuters Connect) The 49ers have spent all week bracing for bad news on defense, and they got it on Friday. San Francisco now heads into Sunday’s game against Arizona without one of its most important pieces up front in Nick Bosa. The absence is extra significant, given his history with this exact opponent. He tore his ACL against these same Cardinals last September. This year’s calf issue then landed on top of a knee the team has monitored closely since training camp. NBC Sports Bay Area’s Jennifer Lee Chan only just raised serious concerns about the severity of the setback . Friday’s news confirmed exactly what she feared. The 49ers have officially ruled Bosa out against the Cardinals, according to NFL Network’s Ian Rapoport . He and ESPN’s Adam Schefter report that Bosa suffered a calf injury in practice and is now expected to miss multiple weeks. Rapoport And Schefter Both Point To An Extended Absence ...