Gray was released by the Dolphins on Tuesday, the Miami Herald reports.
Rookie running back Jay Ajayi gained 41 yards on five carries in Sunday's 33-17 loss to the Bills, likely establishing himself as Lamar Miller's top backup in the process. Gray thus became expendable, but he could latch on with another team by the end of the week. His former squad, the Patriots, just lost Dion Lewis (knee) for the rest of the season.