Sundowns were knocked out in the group stages of the ongoing Champions League campaign, but will be back when the competition kicks off again in December.
The 2019 Africa Cup of Nations has been moved from January to June, which means the Champions League will run from December to May.
The 2016 champions had a difficult campaign this year, winning just one of their six group stages matches. Mosimane wants his men to be ready when they return later this year.
“We are trying to prepare this team for the Champions League later this year,” Mosimane said.
“It’s very difficult and that’s why I tell Sundowns’ supporters that they must be a little bit patient with us because we have a new line of four people upfront who are new. We’ll get there, slowly. We are preparing for the Champions League but we have to use the league to prepare for the Champions League because you know what’s key for us – it’s the Champions League. We want to represent South Africa for a sixth year in a row because we can’t let the country down.
He continued: “National agenda is important for us. We will play the top eight again next year, just like the Nedbank Cup and the Telkom Knockout. So you don’t have to worry much about those ones. You must worry about the big ones, the grand slams. There are tournaments and there are grand slams. We want the grand slams.”