All NFL teams had to trim their rosters from 80 to 53 by Saturday's deadline. Meriweather, the 2007 first-round pick has never missed a game, registering 40 regular-season starts.
The Patriots released veteran safety James Sanders on Monday, and parting ways with Meriweather further gives the safety spot a new look.
Third-year safety Patrick Chung projects as one starter, with second-year man Sergio Brown a possible candidate to be the other starter. The Patriots also have four-year veteran Josh Barrett and fifth-year man James Ihedigbo on the roster at this point.
Meriweather's shaky status on the roster first came to the forefront when he played the entire first half of the preseason opener. He was the only Pro Bowler on the team to do so, as quarterback Tom Brady, receiver Wes Welker, cornerback Devin McCourty, linebacker Jerod Mayo and defensive lineman Vince Wilfork were among those held out of action.
Then, in Thursday's preseason finale, Meriweather didn't enter until the start of the third quarter and played alongside backups.
On Friday, coach Bill Belichick was asked how Meriweather had performed in training camp.
"It's been good," he responded. "Brandon has been out there every day. He's worked hard. He's been able to do everything and I think he's gotten better, worked a lot on his man-to-man coverage. He's out there practicing like everybody else is."
Meanwhile, veteran running back/fullback Sammy Morris was also released by the Patriots on Saturday.
The Patriots have BenJarvus Green-Ellis and Danny Woodhead atop the depth chart, and then selected Shane Vereen (second round) and Stevan Ridley (third round) high in the draft, so the question all along has been whether the club would keep five backs.
Morris' release, for now, signifies that the number will be four. With the Patriots poised to keep three quarterbacks on the roster for the first time in a few years, another position has to be trimmed, and running back -- where the Patriots have kept five in the past -- looks like the choice.
Richard Medlin, who was with the team in training camp, could possibly join the practice squad to add another layer of depth.
Moore had been working with the first unit at left defensive end for most of training camp, but his hold on a roster spot came into question during the fourth preseason game when Shaun Ellis and Mike Wright played for the first time, both at left end. Prior to that point, it was unclear where the Patriots envisioned Ellis and Wright fitting in to the revamped defense.
The Patriots also released defensive linemen Landon Cohen and Aaron Lavarias, linebackers Niko Koutouvides and Markell Carter, wide receiver Tiquan Underwood, offensive lineman Thomas Austin, running back Eric Kettani, defensive back Ross Ventrone, defensive end Alex Silvestro and tight ends Lee Smith and Will Yeatman.
Mike Reiss covers the Patriots for ESPNBoston.com.