The timetable for Lewis' return is uncertain, according to the report. Lewis tore his left ACL last Nov. 8 against the Washington Redskins.
Lewis participated in one session of organized team activities this spring but began training camp on the physically unable to perform list.
Lewis joined the Patriots on a futures contract in December 2014, and was a breakout star in seven games early last season with 622 yards from scrimmage and four touchdowns. He rushed 49 times for 234 yards and caught 36 passes for 388 yards before suffering the season-ending knee injury.