Cravens missed the first three preseason games while rehabbing a summer knee injury. He played in the team's preseason finale, but the knee flared up and the Broncos said Cravens will now have surgery.
The Broncos were hoping to use Cravens in their "dime packages."
While a member of the Washington Redskins, Cravens sat out the entire 2017 season recovering from post-concussion syndrome.
He will be eligible to return to the active roster mid-season.
McKenzie likely will be the main punt returner. He was among the final cuts on Saturday as the Broncos got down to the 53-man roster limit.