Doncaster won just one of their six league outings in October and McCann feels that a new month can bring better fortunes for his side.
Charlton have enjoyed a decent start at home in League One, losing just two of their eight games at The Valley.
“We need to make sure we get ourselves back into a good run,” admitted McCann.
“We have had a horrible month, we have hopefully got our bad month out of the way.
“Each team will go through a month where they win only one or two games; we have done that.
“We have a new month coming up, a new focus and a new points tally for the boys to try and achieve.
“It is a tough game at The Valley against Charlton, but these are the sort of games you look forward to.”
Doncaster have failed to score in 50 per cent of their league outings in October.
But that statistic is not a worry for the Rovers manager who believes that the chances have not been lacking.
He added: “We are creating chances, I would be a lot more worried if we weren’t creating the chances.
“That is isn’t an issue with me, we will score goals, I have always said that.
“We are one of the highest-scoring teams in the league, we are certainly in the top six.
“We could easily be the top with the amount of chances that we have missed, so we can definitely improve on that.”
McCann revealed that two key players are actually set to miss today’s encounter, but would not divulge which two from his squad would not be making the trip to London.