Gardner has good size and speed, and he's been known to be a playmaker. But he hasn't put it all together as a pro. He's too inconsistent. He's had some good years, but mostly has been considered an underachiever.
He's a player that I had wanted to see the Falcons pursue in this upcoming off-season to compete with Finn for the #3 job. But he's probably got too inconsistent hands and is not a good enough blocker to be anything more than a small blip on the team's radar unless he's still unsigned come May or June.
I suspect if the Falcons do seek veteran help at the #4 spot it will have to be a player that can play special teams and block, something that aren't on Gardner's resume. A player like that is more likely to come in the draft than free agency.
Age is also a factor with Gardner