The Patriots scored just six points in their loss to Marvin Lewis's side as quarterback Tom Brady was held without a touchdown pass for the first time in 53 games.
McDaniels told reporters: "I think that our overall execution in the passing game on Sunday wasn't what we wanted it to be.
"We had some throws that were a little off, and we had some guys that tried to make some tough catches and didn't come up with them, and that's football.
"We certainly don't accept it and we're not going to just stand there and not try to improve and get better at it every week, which we do work extremely hard at that, the guys are doing the same thing."
The Patriots are 4-1 in their season after week five.