San Francisco 49ers running back Christian McCaffrey has been ruled out for the upcoming game against the Minnesota Vikings due to ongoing calf and Achilles injuries. Coach Kyle Shanahan indicated that McCaffrey experienced significant pain on Thursday, marking his worst day health-wise, and the team is now considering placing him on injured reserve, which would sideline him for at least four weeks. This follows McCaffrey's absence in the first game of the season and a frustrating recovery process that began during training camp. In his absence, backup Jordan Mason had a strong performance in the last game, contributing significantly to the team's success. The potential move to injured reserve reflects the team's cautious approach to McCaffrey's health, prioritizing his long-term recovery over immediate game participation.