Rusike hurt his knee in the 1-0 loss to Cape Town City in Tshwane this past weekend and has joined fellow strikers Bradley Grobler and Thembo Mnyamane on the sidelines at Matsatsantsa.
SuperSport, however, have been boosted by the return to training of influential midfielder and captain Dean Furman, who dislocated his shoulder in October last year.
"It's been a concern," United coach Kaitano Tembo said of their injury woes this season.
"Rusike's got a knee injury and is now out probably for two to three weeks. That has been our season.
"Probably we will get Dean, Brad and Thabo [back] in the coming weeks. We need them, we missed them.
"Dean is our captain and the backbone of the team.
"But we must also give credit to the others guys that have displayed good performances for the team."
Meanwhile, Tembo would not comment on speculation that Thuso Phala and Fagrie Lakay are leaving the club in the January transfer window.
Winger Phala has been linked with a move to Orlando Pirates, while forward Lakay is reportedly on Bidvest Wits' radar.
Both men did not feature in the defeat to the Citizens at Lucas Moripe Stadium on Saturday.
"I am not going to comment about that. The club will make a statement if there are changes.
"As far as I am concerned, they are still SuperSport United players until otherwise."