The 2016 Champions League winners face Moroccan side Wydad Casablanca in Rabat on Saturday.
The defending champions reportedly declined an offer from the Premier Soccer League (PSL) to postpone their match with Maritzburg to March 29.
The club felt that the proposed new date at the end of the month would be too close to the first-leg quarterfinals set for April 5.
Downs' acting general manager Yogesh Singh confirmed that the team will leave for Morocco tomorrow morning.
"The team will sleep in Durban and then fly to OR Tambo and then fly out on Wednesday morning," Singh said.
Downs coach Pitso Mosimane conceded that the Maritzburg match came at an awkward time.
"We would have loved to travel to Casablanca and have the whole week to prepare for them but it was not to be," Mosimane said.
"Obviously, the Maritzburg game means we will have two days to prepare for Wydad, so we are in a difficult situation.
"In any competition, even the World Cup or Cup of Nations, 11 points is usually enough to qualify from the group.
Tonight: Maritzburg v Sundowns, Harry Gwala Stadium, 7.30pm
Tomorrow: Baroka v Arrows, Peter Mokaba Stadium, 7.30pm
Friday: SuperSport v Chiefs, Mbombela, 8pm; Celtic v Wits, Dr Molemela Stadium, 8pm; CPT City v Polokwane City, Cape Town Stadium, 8pm
Saturday: FS Stars v AmaZulu, Goble Park, 3.30pm
Sunday: Chippa v Highlands, Nelson Mandela Bay, 3.30pm