Bulls coach Jake White said that the extra travel the South African sides have to do in the URC is putting them at a disadvantage.
After going down to Connacht at the weekend, the Sharks have lost all five of their URC clashes this season.
The Bulls focus on Edinburgh as the league leaders look to complete their European travels with another successful showing in the United Rugby Championship.
The Sharks continued to struggle on their overseas tour as they fell to a 19-5 defeat United Rugby Championship defeat against Ospreys at the Stoop.
Glasgow Warriors scored three first-half tries on the way to defeating United Rugby Championship leaders Stormers 20-9 at Scotstoun.
Three of the four South African teams are on overseas duty for the second week of the United Rugby Championship, with some tough fixtures awaiting them.