Getty San Francisco 49ers RB Christian McCaffrey worked out at altitude with Atlanta Falcons RB Bijan Robinson. After one game, the injury bug has hit the San Francisco 49ers as the team placed tight end George Kittle on injured reserve with a hamstring injury on Tuesday. Kittle, injured in the first half of Sunday’s win over the Seattle Seahawks , will be sidelined for the next four games: at New Orleans Saints , at home against the Arizona Cardinals and Jacksonville Jaguars , and at the Los