Rangers have only played one pre-season match ahead of their group opener against Motherwell at Fir Park, and Warburton utilised his squad in the game against Charleston Battery in the United States.
Rangers also face Annan, East Stirlingshire and Stranraer in the subsequent eight days and Warburton will focus on getting his squad ready for their league opener.
Warburton said: “The ideal situation would be to play Motherwell and both teams be able to play seven or eight substitutes. What we are going to face now is a very prestigious competition and eight boys will play 90 minutes. That’s far from ideal.
“We have played 45 minutes. We broke up on May 22 and had three and a half weeks off after the cup final and straight back into it. So it’s not as if we have given them an extended break.
“It’s a tough one: to play four games in nine days is a far from ideal scenario. It’s a demanding schedule so early in the season. I don’t understand that personally, but it is what it is and we have to deal with it as many other teams have to do.
“We will do what we have to do but all our focus has to be August 6 against Hamilton in the first league game. But we are in no way devaluing from what is a very prestigious competition.
“Motherwell will be a very tough opponent.”
Motherwell manager Mark McGhee has dismissed any concerns over lingering bad feeling from the 2015 play-off final between the club, which ended with then Ibrox defender Bilel Mohsni punching home striker Lee Erwin and some Motherwell fans invading the pitch and taunting the visiting support.
McGhee said: “We are a club that welcome Rangers big time back into the league. As a competition, I think it’s better off with Rangers.
“There need be no bad feeling about that. Play-off games are emotional.”