The reason why the 49ers have yet to sign quarterback Alex Smith yet became very clear Friday when reports surfaced that the team not only has shown interest in free-agent quarterback Peyton Manning but were the first to watch him throw. ESPN reported on Friday that 49ers coach Jim Harbaugh and offensive coordinator Greg Roman flew to North Carolina on Tuesday to watch the 11-time Pro Bowl quarterback, who is recovering from multiple neck surgeries, throw and to give him a physical.