Denver, for all its well-earned defensive plaudits, was too vulnerable in the middle of the field. With good health, that should change.

The 49ers have to figure out what to do at weakside linebacker. Dre Greenlaw is coming off a season in which he played just 34 snaps after tearing his Achilles in last year's Super Bowl.

After letting Cody Barton walk in free agency, the Broncos now have Alex Singleton, Drew Sanders, Levelle Bailey and K.J.