Dre Greenlaw
Greenlaw earned the starting Sam job as a rookie fifth-round pick, and he earned more playing time as the Will when Alexander went down with a pectoral injury in Week 10. Greenlaw played well in that spot and came up with the biggest tackle of the year in Week 17 when he stopped Seahawks tight end Jacob Hollister short of the goal line to preserve the 49ers’ victory. Greenlaw might’ve done enough last year to earn the starting spot at Will, but he’ll need to prove he can back up his play in his second season to take over that job again.