FLOWERY BRANCH, Ga. — Veteran Dwight Freeney and rookie Keanu Neal, newcomers who carry big expectations on Atlanta’s defense, are expected to make their preseason debuts against Cleveland on Thursday night. Freeney, the defensive end, was held out of last week’s preseason opener against Washington after reaching a deal with the team early this month. Neal, the team’s first-round draft pick from Florida, is projected as the starting strong safety.