2. Christian McCaffrey might not stay healthy
The Carolina Panthers didn't deal Christian McCaffrey to the 49ers solely because they were ready to engage in a roster rebuild. A big part of Carolina's motivation was their realization that they could not trust the versatile running back to stay healthy throughout a full season.
The 49ers front office decided they'd roll the dice and trust McCaffrey to be a key cog in a championship offense. That will require him to be fresh once the postseason begins. The fact that he's already dealing with an oblique injury should be setting off alarm bells in San Francisco.
Look for the 49ers to try to rest McCaffrey whenever they can. He shouldn't play a regular season game where he's feeling anything less than 100%. The problem with that philosophy is that the team really doesn't have a quality option behind McCaffrey on the depth chart to rely on.
That's going to cause Shanahan and his offensive staff to overuse McCaffrey before the postseason arrives. Every touch he absorbs during a meaningless regular season contest is a chance the 49ers really shouldn't be taking. At his best, he's just the sort of player who can turn a loss into a win all on his own.
Unfortunately for McCaffrey and the 49ers, availability is a skill in the modern NFL. It's a skill McCaffrey lacks and it's going to cost San Francisco the chance to win a title.