McGarrahan figured he was going to get cut anyway because he stood as the sixth safety and the Dolphins will only keep five.
McGarrahan rejoined the team for which he played three seasons (1998-2000) before he joined the Dolphins in 2001.
"It's good for Scott," said Coach Dave Wannstedt. "He's a winner. He helped us win a lot of game, it's just that the numbers were just tight there at safety."
They joined nine other players who were released on Saturday: TE Dejhown Mandley, WR Jimmy Fryzel, T Morgan Pears, T Mark Bristol, G Dwayne Pierce, DT Tavares Jurineack, LB Devin Lemons, CB Cedric Donaldson and DB Terrance Leftwich.
The Dolphins still have a few moves left to make and they have until Tuesday at 4 p.m. ET to do so.