Wochit News - The Buffalo Bills have traded receiver Stevie Johnson to the San Francisco 49ers. Buffalo announced the trade on Friday, saying in return they acquired an undisclosed pick in next year's NFL draft. ESPN reported it was a conditional fourth-round selection. The deal was made a day after the Bills traded up five spots to get Clemson receiver Sammy Watkins with the fourth pick in the draft. The 49ers had a need for an experienced receiver after losing Mario Manningham in free agency.