49ers' McCaffrey and Mason sidelined with injuries, impacting season plans

San Francisco 49ers running back Christian McCaffrey will miss the rest of the regular NFL season due to a posterior cruciate ligament injury in his right knee, though surgery is not required. This marks his second stint on injured reserve this season, following an Achilles injury. The 49ers, currently last in the NFC West, also lost backup Jordan Mason to a high ankle sprain. Coach Kyle Shanahan expressed sympathy for McCaffrey's challenging season, while the team plans to rely on rookie Isaac Guerendo and promote Patrick Taylor from the practice squad.