Neblett, originally an undrafted free agent out of Temple in 2010, was with the Panthers from 2010-2012 and spent this preseason with the Buccaneers. He was previously brought in by the Patriots for a workout.
Neblett, 6-foot and 310 pounds, gives the Patriots an additional body along the interior of the defensive line, where they played their first game without Vince Wilfork in Week 5. The team had just three defensive tackles on the roster before signing Neblett, and veteran Tommy Kelly was banged-up in Week 5 with a knee injury.
The 25-year old Neblett has 40 career tackles and three sacks to his name.
The Patriots also filled out their practice squad by re-signing defensive back Kanorris Davis and linebacker Ja'Gared Davis.
Each player was promoted from the practice squad to the active roster on Saturday in advance of the team's Week 5 game in Cincinnati. They were subsequently waived on Monday and cleared through waivers on Tuesday, making them free agents.
Kanorris Davis played 21 special-teams snaps against the Bengals, while Ja'Gared Davis logged six special-teams snaps.