Moodie has been ruled out under head injury assessment (HIA) protocols after colliding with Lions loose forward Siba Mahashe during the Bulls' emphatic 57-15 United Rugby Championship victory in Pretoria last weekend.
The 23-year-old had already scored a try and troubled the Lions' defence with several line breaks before leaving the field early in the second half.
His absence is a setback for the Pretoria side as they begin their European campaign, with fellow winger Cheswill Jooste also struggling with illness.
Ackermann could turn to Stravino Jacobs, Sebastian de Klerk or Dylan Maart to fill the gap out wide, with the Bulls set to announce their team on Thursday.
There is some positive news for the coach, however, as scrumhalf Embrose Papier has returned to training after a lengthy spell out with an ankle injury. Hooker Akker van der Merwe remains unavailable as he continues to recover from a calf problem.
The Bulls will be aiming for a strong start to their Champions Cup campaign after reaching the knockout stages last season, when their run ended with a last-16 defeat to Glasgow Warriors.
Their best performance in the competition came in 2023/24, when they reached the quarterfinals before losing 59-22 to Northampton Saints.
Handre Pollard returns at flyhalf and Luan Giliomee earns his first start at fullback as the Bulls named their team for Saturday's Investec Champions Cup opener against Stade Francais.
Bulls fly-half Luan Giliomee revealed that joining the Bulls has been a positive and welcoming experience, praising the support he has received from teammates and the coaching staff.
Stormers head coach John Dobson and captain Ruhan Nel have issued a clear warning about the threat posed by Bristol Bears ahead of their Champions Cup opener on Saturday.
Evan Roos will make his first appearance of the season when the Stormers launch their Champions Cup campaign against Bristol Bears in Cape Town on Saturday.
