Hull ensured a fifth round replay against Championship outfit Brighton and Hove Albion on Monday, with Yannick Sagbo salvaging a 1-1 draw at the Amex Stadium in the closing stages after Leonardo Ulloa had put Oscar Garcia's men into a first-half lead.
The two will now battle again at the KC Stadium next Monday for the right to face Sunderland in the quarter-finals.
That fixture will come just two days after Hull travel to Cardiff City for a Premier League encounter, and Bruce was left flabbergasted by the scheduling of the replay.
"I find that ridiculous, I have to tell you," Bruce said.
"Surely we could play on the same night as the Champions League, you would have thought.
"I think it is a UEFA rule, which reads nobody plays on the same night as the Champions League. We'll have to take it as it is and deal with it as it comes.
"It is quite a bizarre one, isn't it? For them to say to the FA that we can't play the same night as they are playing the Champions League.
"I don't think there will be many tuning out of Barcelona against Manchester City to tune into Hull versus Brighton, no disrespect.
"But there you have it, they think it's going to clash. Is it going to be a real problem for them? I somehow doubt it."
That view was shared by opposite number Garcia, whose side host Wigan Athletic two days before making the long journey to Hull.
"It's not good for anyone to play two games in three days," he added. "But there's not much we can do.
"The travelling will not go in our favour, it's not the best scenario for us but we just have to focus on this game and try to win."
