The Bees reached the semi-finals of the competition last season, but Frank says his players can't get ahead of themselves.
"In football nothing is easy," Frank said. "We've seen it so many times that there's been surprises in the Carabao Cup or the FA Cup.
"Premier League sides getting beaten by Conference teams or League Two sides. That can happen tomorrow, so we're very aware of that.
"Of course we are favourites, of course I expect us to win, but I know that Oldham can hurt us.
"We are prepared for this game as good as we were against Wolves and I will put a strong team out there that I 100 per cent think can win the game.
"But we know it's the small things in football that can change so quickly in the game."
Need a VPN? Or seeking to switch? Then support Tribal Football by clicking here to sign up with our official partners NordVPN. Not only will you receive the best VPN experience, but also great discounts by signing up via Tribal Football. Thanks for your support!