O'Donnell reverted to the Falcons' practice squad before being let go by the team Monday, Terrin Waack of the team's official site reports.
O'Donnell was added to the practice squad and subsequently elevated to the active roster Saturday with Bradley Pinion dealing with an illness. Pinion was able to play Sunday, so O'Donnell's services were not needed and he was inactive for the game. He'll explore his options once he clears waivers.