SANTA CLARA, Calif. -- The San Francisco 49ers' practice field is an amazingly talented place these days.In what has a chance to be one of the most compelling storylines in the NFL in the second half, the 49ers are getting mass reinforcements.The 49ers (6-2) had their bye in Week 9 following a five-game winning streak, and the off week was not a quiet one.They activated four players who could all have an impact: pass-rusher Aldon Smith, receiver Mario Manningham, cornerback Eric Wright and rookie defensive lineman Tank Carradine.