The poor performance of Hull's periphery players in east London will be of concern to Bruce as he looks ahead to a tough season back in the top flight.
"You don't want to undermine it, of course you don't," he said of the 11 changes.
"You want to give your squad a chance because the difficulty of playing in the Premier League is that it makes this the ideal opportunity to play the squad.
"They've played this evening but we all know the Premier League has got to be the priority.
"We are new in there and we've got to make sure we do everything we possibly can to stay up, keep the squad intact.
"The more games you play, the more chance you have of getting an injury to your big players and that is always in the back of your mind.
"We're delighted we got there, but it wasn't a great performance. Orient played very well on the night."
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