The Buccaneers returned to winning ways following their MTN8 final disappointment, with goals from Boitumelo Radiopane, Tshepang Moremi and Simphiwe Masilela securing a convincing victory at the Orlando Amstel Arena.
However, the Buccaneers were dealt a potential injury blow when Appollis was stretchered off in the 55th minute after providing the assist for Radiopane's opening goal.
With the Soweto giants entering a crucial period of the season, the attacker's fitness will be a major concern, particularly with a CAF Champions League fixture and the Soweto Derby against Kaizer Chiefs on the horizon.
Speaking to the media, Ouaddou suggested that fatigue could be responsible for the setback but admitted that the club would need to conduct further assessments before determining the extent of the problem.
"It seems to be fatigue, I hope, really because he is one of our most important players. We have an important game now in the Champions League. We have the derby coming," he said.
"For now, I don't have all the information about that (injury). I just did not want to take the risk with him. He is a very important player. When I spoke with him and the medical department, we just decided not to take the risk. We will assess him, and maybe we will have more information."
The 25-year-old has been one of Pirates' standout performers this season, contributing two goals and three assists in eight Betway Premiership appearances.
Following their win against Galaxy, the Buccaneers remain in second place on the league standings with 22 points, one point behind leaders Sundowns, but Bucs have a game in hand.
With Appollis injury concerns, Pirates now turn their attention to the CAF Champions League, where they face African Stars FC in the second preliminary round at the National Stadium in Botswana on Saturday with a place in the group stages at stake.
