SANTA CLARA, Calif. -- It won't happen, but the San Francisco 49ers can extend the contracts of both Colin Kaepernick and Aldon Smith as soon as Monday.By rule, teams can start negotiating contracts with players who were taken in the 2011 draft. Smith was the 49ers' first-round pick and Kaepernick was the team's second-round pick. Next season will be the final contract year for both players. Both are cornerstone players whom the 49ers intend to keep.