Bethel (knee) was not included among the Dolphins' inactive players ahead of Sunday's contest with the Chargers.
The Dolphins re-signed Bethel on Friday, David Furones of the South Florida Sun Sentinel reports.
Bethel recorded two passes defended and seven tackles (five solo) during Sunday's 39-17 win versus the Browns.
Bethel was released by the Patriots on Tuesday, Field Yates of ESPN reports.
Bethel signed a 3-year, $6 million deal with the Patriots on Friday, Mike Reiss of ESPN.com reports.
The Patriots signed Bethel to an undisclosed contract Tuesday, Ian Rapoport of NFL Network reports.
Bethel was released by the Ravens on Monday in order to recoup a compensatory draft pick, Jonas Shaffer of The Baltimore Sun reports. "That's tough for us because, I told him, I think he's the best special teams player in the NFL, and he's playing that way," said head coach John Harbaugh. "So that's going to be a blow, and we're going to have to find a way to overcome that."
Bethel and the Ravens agreed on a two-year deal on Friday.
Bethel recorded 12 solo tackles and two assisted tackles for the Falcons in 2018.
Bethel (ankle) was a limited participant in Friday's practice, Vaughn McClure of ESPN.com reports.