Right tackle Anthony Davis announced his retirement from the San Francisco 49ers in yet another shocking loss for the team this offseason, and it was unclear whether the decision stemmed from his difficulties with a concussion last year. The 25-year-old Davis informed the team Friday through his usual way of communicating: He sent a text message to coach Jim Tomsula before his old teammates practiced. ''After a few years of thought, I've decided it will be best for me to take a year or so away from the NFL. More...