The NFC South champions were beaten 20-16 by the Jacksonville Jaguars, leaving them without a win in pre-season.
The head coach told reporters: "The biggest concern is the number of penalties. We had nine penalties, we had personal fouls, one in the kicking game, and one on third down. I don't think we have been as efficient as we need to as a team on third down.
"Again, tonight we were only 24% in our third down efficiency. Those are probably the three things. Again, that is the entire team, not just the ones or twos or threes. We've got to look at who is taking the snaps and when they are taking the snaps as well.
"Every time you go out on the field, as a competitor you want to win. No doubt about that. Everybody in the organisation that is what we want to do. Our number one goal in the pre-season, behind winning, is to evaluate these guys, put them in situations that we need to find out about these guys."
The Falcons face the New Orleans Saints in their opening game of the season.