San Francisco 49ers linebacker Chris Borland walked away from the NFL at the age of 24 for fear of head injuries, despite not having a diagnosed concussion for a decade. And then there’s Wes Welker, the anti-Borland, a wideout with a disturbing array of concussions who isn’t ready to quit. “As long as I’ve recovered the right way and everything like that, I’m ready to go,” Welker told ESPN in December. “I really don’t see any problem with it.’’ But apparently the rest of the NFL sees what Welker doesn’t. Pro Football Talk reported the receiver has “generated no buzz”...