Terrell had been on the injury report all week after suffering a concussion in the first quarter of last week's win over the New York Jets while trying to tackle Breece Hall, a play that saw Hall later fined $43,709.
On Saturday, the team announced Terrell cleared concussion protocol.
He practiced all week, first on a limited basis and then fully Friday. Falcons coach Arthur Smith said they would see how Terrell felt and lean on what the doctors said before making a decision on his availability.
This will be a benefit for Atlanta, which ruled out two defensive starters Friday (defensive lineman David Onyemata and linebacker Nate Landman) and also has cornerbacks Jeff Okudah (ankle) and Mike Hughes (hand) listed as questionable.
The Falcons also elevated offensive tackle Tyler Vrabel and linebacker Milo Eifler from the practice squad for Sunday, likely to help with injuries since Landman (knee) and starting right tackle Kaleb McGary (knee) have been ruled out.