ESPN first reported the development.
Starting the season on the PUP list was the expected outcome for the shifty back. Lewis suffered a torn ACL last November and underwent an additional procedure this summer. Vollmer suffered a leg injury in Week 16 of the 2015 season.
Lewis was a revelation in New England last season, toting the rock 49 time for 234 yards, 4.8 average. His biggest attribute was as a pass catcher for Tom Brady. The elusive runner was deadly in the open field prior to the knee injury, catching 36 passes for 388 yards.