49ers' rookie QB Purdy impresses, defense dominates as team prepares for playoff run

Purdy's rapid development has drawn comparisons to greats like Brady and Montana.
The 49ers defense is among the league leaders in pressures and sacks.
RB McCaffrey is comfortable with a heavy workload going into the postseason.
ers cornerback depth chart remains uncertain due to injuries.
K Robbie Gould's occasional kickoff issues could impact field position in playoffs.