Hardy missed the majority of the 2014 season as he was placed on the commissioner's exempt list while facing charges of domestic violence. However, the charges were dropped at the beginning of the year, allowing the 26-year-old to sign a one-year deal with the Cowboys.
The defensive end could still face a suspension from the NFL, and Davis is hopeful that the ban could prevent Hardy from facing his former team.
"No one really knows what the league's going to do suspension-wise," Davis told reporters. "But I hope we play them early in the season and we don't have to face him.
"I hope he's not that good and it doesn't really work out for Dallas. But I know Hardy and I know what kind of player he is. He's going to go in and he's going to work his butt off. He's definitely going to make that defense better."
Hardy recorded 204 tackles and 34 sacks in his five seasons with the Panthers.