Shanahan is such an elite play caller that the 49ers can withstand an injury to McCaffrey for a few weeks. After all, they still have George Kittle, Brandon Aiyuk and Deebo Samuel as weapons on that side of the ball. However, McCaffrey's versatility and ability to line up anywhere and hurt the defense in multiple ways would be severely missed if he was forced to miss extended time. The fact that injured reserve isn't even on the table at this moment is a major positive for San Francisco.