He said he has not worn it since he began working out in February.
A source said Smith is looking Notre Dame-fast again and primed for a big year after just being happy to get in the field in 2017. He missed all of 2016 recovering from injuries to his anterior cruciate and lateral collateral ligaments in his left knee and overcoming damage to the peroneal nerve in his final game at Notre Dame.
Smith, who was better in small doses than extended stretches of action last year, finished second in the team with 99 tackles in 2017 despite wearing a brace on his left foot and ankle due to drop foot.
Smith said he's the healthiest he's been since he joined the Cowboys as a second-round pick in 2016.
He expects a big year because he is finally able to run loose and free without the brace.
"Getting that flexion back is going to help tremendously ... speed, quickness, explosiveness," Smith said. "I have been feeling great. Everything is about getting back to 100 percent. Every day I am improving."